Gecko [ fernandoquevedodop.com ]

Name	Size	Permission
2to3.html	70.96 KB	-rw-r--r--
__future__.html	20.75 KB	-rw-r--r--
__main__.html	44.87 KB	-rw-r--r--
_thread.html	30.39 KB	-rw-r--r--
abc.html	46.87 KB	-rw-r--r--
aifc.html	35.56 KB	-rw-r--r--
allos.html	34.33 KB	-rw-r--r--
archiving.html	17 KB	-rw-r--r--
argparse.html	300.89 KB	-rw-r--r--
array.html	37.28 KB	-rw-r--r--
ast.html	293.08 KB	-rw-r--r--
asynchat.html	37.41 KB	-rw-r--r--
asyncio-api-index.html	27.68 KB	-rw-r--r--
asyncio-dev.html	36.1 KB	-rw-r--r--
asyncio-eventloop.html	204.43 KB	-rw-r--r--
asyncio-exceptions.html	17.11 KB	-rw-r--r--
asyncio-future.html	38.23 KB	-rw-r--r--
asyncio-llapi-index.html	61.97 KB	-rw-r--r--
asyncio-platforms.html	21.77 KB	-rw-r--r--
asyncio-policy.html	39.56 KB	-rw-r--r--
asyncio-protocol.html	118.33 KB	-rw-r--r--
asyncio-queue.html	31.86 KB	-rw-r--r--
asyncio-stream.html	69.98 KB	-rw-r--r--
asyncio-subprocess.html	49.25 KB	-rw-r--r--
asyncio-sync.html	42.79 KB	-rw-r--r--
asyncio-task.html	109.14 KB	-rw-r--r--
asyncio.html	17.31 KB	-rw-r--r--
asyncore.html	49.36 KB	-rw-r--r--
atexit.html	22.87 KB	-rw-r--r--
audioop.html	46 KB	-rw-r--r--
audit_events.html	72.85 KB	-rw-r--r--
base64.html	48.09 KB	-rw-r--r--
bdb.html	66 KB	-rw-r--r--
binary.html	15.97 KB	-rw-r--r--
binascii.html	36.3 KB	-rw-r--r--
binhex.html	15.97 KB	-rw-r--r--
bisect.html	43.38 KB	-rw-r--r--
builtins.html	14.87 KB	-rw-r--r--
bz2.html	50.68 KB	-rw-r--r--
calendar.html	69.35 KB	-rw-r--r--
cgi.html	59.95 KB	-rw-r--r--
cgitb.html	19.96 KB	-rw-r--r--
chunk.html	22.21 KB	-rw-r--r--
cmath.html	43.89 KB	-rw-r--r--
cmd.html	50.42 KB	-rw-r--r--
code.html	35.38 KB	-rw-r--r--
codecs.html	157.96 KB	-rw-r--r--
codeop.html	18.26 KB	-rw-r--r--
collections.abc.html	79.17 KB	-rw-r--r--
collections.html	189.43 KB	-rw-r--r--
colorsys.html	17.31 KB	-rw-r--r--
compileall.html	50.68 KB	-rw-r--r--
concurrency.html	24.15 KB	-rw-r--r--
concurrent.futures.html	79.03 KB	-rw-r--r--
concurrent.html	11.56 KB	-rw-r--r--
configparser.html	159.4 KB	-rw-r--r--
constants.html	22.41 KB	-rw-r--r--
contextlib.html	117.2 KB	-rw-r--r--
contextvars.html	38.38 KB	-rw-r--r--
copy.html	17.92 KB	-rw-r--r--
copyreg.html	18.63 KB	-rw-r--r--
crypt.html	28.29 KB	-rw-r--r--
crypto.html	13.93 KB	-rw-r--r--
csv.html	82.89 KB	-rw-r--r--
ctypes.html	295.49 KB	-rw-r--r--
curses.ascii.html	32.04 KB	-rw-r--r--
curses.html	221.24 KB	-rw-r--r--
curses.panel.html	22.16 KB	-rw-r--r--
custominterp.html	11.85 KB	-rw-r--r--
dataclasses.html	113.16 KB	-rw-r--r--
datatypes.html	31.82 KB	-rw-r--r--
datetime.html	374.92 KB	-rw-r--r--
dbm.html	51.16 KB	-rw-r--r--
debug.html	17 KB	-rw-r--r--
decimal.html	270.12 KB	-rw-r--r--
development.html	32.34 KB	-rw-r--r--
devmode.html	31.72 KB	-rw-r--r--
dialog.html	43.03 KB	-rw-r--r--
difflib.html	111.99 KB	-rw-r--r--
dis.html	136.07 KB	-rw-r--r--
distribution.html	13.67 KB	-rw-r--r--
distutils.html	14.73 KB	-rw-r--r--
doctest.html	199.32 KB	-rw-r--r--
email.charset.html	31.92 KB	-rw-r--r--
email.compat32-message.html	97.74 KB	-rw-r--r--
email.contentmanager.html	37.02 KB	-rw-r--r--
email.encoders.html	18.47 KB	-rw-r--r--
email.errors.html	24.45 KB	-rw-r--r--
email.examples.html	60.49 KB	-rw-r--r--
email.generator.html	48.79 KB	-rw-r--r--
email.header.html	37.61 KB	-rw-r--r--
email.headerregistry.html	66.26 KB	-rw-r--r--
email.html	30.75 KB	-rw-r--r--
email.iterators.html	18.23 KB	-rw-r--r--
email.message.html	99.75 KB	-rw-r--r--
email.mime.html	44.89 KB	-rw-r--r--
email.parser.html	57.39 KB	-rw-r--r--
email.policy.html	84.24 KB	-rw-r--r--
email.utils.html	42.57 KB	-rw-r--r--
ensurepip.html	23.9 KB	-rw-r--r--
enum.html	151 KB	-rw-r--r--
errno.html	60.17 KB	-rw-r--r--
exceptions.html	108.44 KB	-rw-r--r--
faulthandler.html	31.5 KB	-rw-r--r--
fcntl.html	36.67 KB	-rw-r--r--
filecmp.html	32.08 KB	-rw-r--r--
fileformats.html	13.52 KB	-rw-r--r--
fileinput.html	40.37 KB	-rw-r--r--
filesys.html	16.78 KB	-rw-r--r--
fnmatch.html	21.02 KB	-rw-r--r--
fractions.html	35.29 KB	-rw-r--r--
frameworks.html	16.15 KB	-rw-r--r--
ftplib.html	71.97 KB	-rw-r--r--
functional.html	12.19 KB	-rw-r--r--
functions.html	260.33 KB	-rw-r--r--
functools.html	92.96 KB	-rw-r--r--
gc.html	40.97 KB	-rw-r--r--
getopt.html	29.4 KB	-rw-r--r--
getpass.html	16.01 KB	-rw-r--r--
gettext.html	98.02 KB	-rw-r--r--
glob.html	27.2 KB	-rw-r--r--
graphlib.html	34.82 KB	-rw-r--r--
grp.html	16.03 KB	-rw-r--r--
gzip.html	45.65 KB	-rw-r--r--
hashlib.html	93.19 KB	-rw-r--r--
heapq.html	42.43 KB	-rw-r--r--
hmac.html	24.74 KB	-rw-r--r--
html.entities.html	14.91 KB	-rw-r--r--
html.html	14.81 KB	-rw-r--r--
html.parser.html	47.7 KB	-rw-r--r--
http.client.html	85.63 KB	-rw-r--r--
http.cookiejar.html	113.94 KB	-rw-r--r--
http.cookies.html	47.64 KB	-rw-r--r--
http.html	45.52 KB	-rw-r--r--
http.server.html	73.05 KB	-rw-r--r--
i18n.html	13.44 KB	-rw-r--r--
idle.html	77.18 KB	-rw-r--r--
imaplib.html	87.08 KB	-rw-r--r--
imghdr.html	17.94 KB	-rw-r--r--
imp.html	54.32 KB	-rw-r--r--
importlib.html	239.96 KB	-rw-r--r--
importlib.metadata.html	43.14 KB	-rw-r--r--
index.html	75.06 KB	-rw-r--r--
inspect.html	168.74 KB	-rw-r--r--
internet.html	29.89 KB	-rw-r--r--
intro.html	13.81 KB	-rw-r--r--
io.html	154.15 KB	-rw-r--r--
ipaddress.html	137.75 KB	-rw-r--r--
ipc.html	12.6 KB	-rw-r--r--
itertools.html	153.27 KB	-rw-r--r--
json.html	98.9 KB	-rw-r--r--
keyword.html	14.88 KB	-rw-r--r--
language.html	16.71 KB	-rw-r--r--
linecache.html	18.09 KB	-rw-r--r--
locale.html	77.35 KB	-rw-r--r--
logging.config.html	100.3 KB	-rw-r--r--
logging.handlers.html	146.28 KB	-rw-r--r--
logging.html	169.67 KB	-rw-r--r--
lzma.html	66.89 KB	-rw-r--r--
mailbox.html	176.34 KB	-rw-r--r--
mailcap.html	20.86 KB	-rw-r--r--
markup.html	22.31 KB	-rw-r--r--
marshal.html	24.43 KB	-rw-r--r--
math.html	85.82 KB	-rw-r--r--
mimetypes.html	40.27 KB	-rw-r--r--
mm.html	11.16 KB	-rw-r--r--
mmap.html	55.53 KB	-rw-r--r--
modulefinder.html	23.67 KB	-rw-r--r--
modules.html	15.88 KB	-rw-r--r--
msilib.html	78.38 KB	-rw-r--r--
msvcrt.html	29.22 KB	-rw-r--r--
multiprocessing.html	405.24 KB	-rw-r--r--
multiprocessing.shared_memory....	60 KB	-rw-r--r--
netdata.html	20.24 KB	-rw-r--r--
netrc.html	20.39 KB	-rw-r--r--
nis.html	16.76 KB	-rw-r--r--
nntplib.html	84.93 KB	-rw-r--r--
numbers.html	45.67 KB	-rw-r--r--
numeric.html	19.29 KB	-rw-r--r--
operator.html	107.32 KB	-rw-r--r--
optparse.html	256.96 KB	-rw-r--r--
os.html	594.39 KB	-rw-r--r--
os.path.html	65.54 KB	-rw-r--r--
ossaudiodev.html	56.35 KB	-rw-r--r--
pathlib.html	170.01 KB	-rw-r--r--
pdb.html	68.67 KB	-rw-r--r--
persistence.html	19.13 KB	-rw-r--r--
pickle.html	154.45 KB	-rw-r--r--
pickletools.html	22.92 KB	-rw-r--r--
pipes.html	21.7 KB	-rw-r--r--
pkgutil.html	42.76 KB	-rw-r--r--
platform.html	45.08 KB	-rw-r--r--
plistlib.html	30.06 KB	-rw-r--r--
poplib.html	41.42 KB	-rw-r--r--
posix.html	20.96 KB	-rw-r--r--
pprint.html	55.35 KB	-rw-r--r--
profile.html	84.63 KB	-rw-r--r--
pty.html	23.7 KB	-rw-r--r--
pwd.html	16.84 KB	-rw-r--r--
py_compile.html	29 KB	-rw-r--r--
pyclbr.html	24.06 KB	-rw-r--r--
pydoc.html	19.59 KB	-rw-r--r--
pyexpat.html	104.38 KB	-rw-r--r--
python.html	22.46 KB	-rw-r--r--
queue.html	43.39 KB	-rw-r--r--
quopri.html	18.64 KB	-rw-r--r--
random.html	86.31 KB	-rw-r--r--
re.html	214.24 KB	-rw-r--r--
readline.html	50.19 KB	-rw-r--r--
reprlib.html	30.85 KB	-rw-r--r--
resource.html	48.26 KB	-rw-r--r--
rlcompleter.html	18.06 KB	-rw-r--r--
runpy.html	30.99 KB	-rw-r--r--
sched.html	27.04 KB	-rw-r--r--
secrets.html	30.2 KB	-rw-r--r--
security_warnings.html	16.21 KB	-rw-r--r--
select.html	74.58 KB	-rw-r--r--
selectors.html	41.91 KB	-rw-r--r--
shelve.html	36.54 KB	-rw-r--r--
shlex.html	61.03 KB	-rw-r--r--
shutil.html	100.13 KB	-rw-r--r--
signal.html	95.39 KB	-rw-r--r--
site.html	38.16 KB	-rw-r--r--
smtpd.html	44.09 KB	-rw-r--r--
smtplib.html	81.4 KB	-rw-r--r--
sndhdr.html	16.4 KB	-rw-r--r--
socket.html	256.95 KB	-rw-r--r--
socketserver.html	91.95 KB	-rw-r--r--
spwd.html	16.71 KB	-rw-r--r--
sqlite3.html	225.51 KB	-rw-r--r--
ssl.html	328.83 KB	-rw-r--r--
stat.html	57.79 KB	-rw-r--r--
statistics.html	123.22 KB	-rw-r--r--
stdtypes.html	615.43 KB	-rw-r--r--
string.html	108.03 KB	-rw-r--r--
stringprep.html	24.94 KB	-rw-r--r--
struct.html	70.58 KB	-rw-r--r--
subprocess.html	199.03 KB	-rw-r--r--
sunau.html	39.84 KB	-rw-r--r--
superseded.html	26.21 KB	-rw-r--r--
symtable.html	33.26 KB	-rw-r--r--
sys.html	198.83 KB	-rw-r--r--
sysconfig.html	39.81 KB	-rw-r--r--
syslog.html	27.36 KB	-rw-r--r--
tabnanny.html	16.18 KB	-rw-r--r--
tarfile.html	161.92 KB	-rw-r--r--
telnetlib.html	38.21 KB	-rw-r--r--
tempfile.html	58.39 KB	-rw-r--r--
termios.html	22.86 KB	-rw-r--r--
test.html	222.85 KB	-rw-r--r--
text.html	16.8 KB	-rw-r--r--
textwrap.html	48.83 KB	-rw-r--r--
threading.html	128.33 KB	-rw-r--r--
time.html	107.46 KB	-rw-r--r--
timeit.html	52.63 KB	-rw-r--r--
tk.html	28.08 KB	-rw-r--r--
tkinter.colorchooser.html	14.49 KB	-rw-r--r--
tkinter.dnd.html	17.09 KB	-rw-r--r--
tkinter.font.html	22.21 KB	-rw-r--r--
tkinter.html	106.85 KB	-rw-r--r--
tkinter.messagebox.html	20.09 KB	-rw-r--r--
tkinter.scrolledtext.html	14.52 KB	-rw-r--r--
tkinter.tix.html	59.69 KB	-rw-r--r--
tkinter.ttk.html	138.37 KB	-rw-r--r--
token.html	45.73 KB	-rw-r--r--
tokenize.html	39.86 KB	-rw-r--r--
trace.html	38.85 KB	-rw-r--r--
traceback.html	75.61 KB	-rw-r--r--
tracemalloc.html	122.33 KB	-rw-r--r--
tty.html	14.46 KB	-rw-r--r--
turtle.html	271.71 KB	-rw-r--r--
types.html	64.85 KB	-rw-r--r--
typing.html	315.69 KB	-rw-r--r--
unicodedata.html	27.3 KB	-rw-r--r--
unittest.html	310.01 KB	-rw-r--r--
unittest.mock-examples.html	177.75 KB	-rw-r--r--
unittest.mock.html	363.51 KB	-rw-r--r--
unix.html	13.46 KB	-rw-r--r--
urllib.error.html	18.56 KB	-rw-r--r--
urllib.html	12.92 KB	-rw-r--r--
urllib.parse.html	104.65 KB	-rw-r--r--
urllib.request.html	208.87 KB	-rw-r--r--
urllib.robotparser.html	22.63 KB	-rw-r--r--
uu.html	18.2 KB	-rw-r--r--
uuid.html	42.88 KB	-rw-r--r--
venv.html	90.43 KB	-rw-r--r--
warnings.html	69.13 KB	-rw-r--r--
wave.html	36.12 KB	-rw-r--r--
weakref.html	73.36 KB	-rw-r--r--
webbrowser.html	33.98 KB	-rw-r--r--
windows.html	12.32 KB	-rw-r--r--
winreg.html	89.48 KB	-rw-r--r--
winsound.html	26.3 KB	-rw-r--r--
wsgiref.html	111.52 KB	-rw-r--r--
xdrlib.html	42.07 KB	-rw-r--r--
xml.dom.html	114.66 KB	-rw-r--r--
xml.dom.minidom.html	49.6 KB	-rw-r--r--
xml.dom.pulldom.html	30.06 KB	-rw-r--r--
xml.etree.elementtree.html	186.49 KB	-rw-r--r--
xml.html	22.34 KB	-rw-r--r--
xml.sax.handler.html	55.78 KB	-rw-r--r--
xml.sax.html	31.74 KB	-rw-r--r--
xml.sax.reader.html	56.23 KB	-rw-r--r--
xml.sax.utils.html	22.28 KB	-rw-r--r--
xmlrpc.client.html	79.73 KB	-rw-r--r--
xmlrpc.html	11.9 KB	-rw-r--r--
xmlrpc.server.html	63.56 KB	-rw-r--r--
zipapp.html	52.45 KB	-rw-r--r--
zipfile.html	116.59 KB	-rw-r--r--
zipimport.html	33.76 KB	-rw-r--r--
zlib.html	42.29 KB	-rw-r--r--
zoneinfo.html	57.25 KB	-rw-r--r--

Code Editor : collections.abc.html

<!DOCTYPE html>

<title>collections.abc — Abstract Base Classes for Containers &#8212; Python 3.10.12 documentation</title><meta name="viewport" content="width=device-width, initial-scale=1.0">
 
 <link rel="stylesheet" type="text/css" href="../_static/pygments.css" />
 <link rel="stylesheet" type="text/css" href="../_static/pydoctheme.css?2022.1" />
 
 <script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js"></script>
 <script src="../_static/jquery.js"></script>
 <script src="../_static/underscore.js"></script>
 <script src="../_static/doctools.js"></script>
 
 <script src="../_static/sidebar.js"></script>
 
 <link rel="search" type="application/opensearchdescription+xml"
 title="Search within Python 3.10.12 documentation"
 href="../_static/opensearch.xml"/>
 <link rel="author" title="About these documents" href="../about.html" />
 <link rel="index" title="Index" href="../genindex.html" />
 <link rel="search" title="Search" href="../search.html" />
 <link rel="copyright" title="Copyright" href="../copyright.html" />
 <link rel="next" title="heapq — Heap queue algorithm" href="heapq.html" />
 <link rel="prev" title="collections — Container datatypes" href="collections.html" />
 <link rel="canonical" href="file:///usr/share/doc/python3.10/html/library/collections.abc.html" />

</head>
<body>
<div class="mobile-nav">
 <input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation"
 aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu" />
 <label for="menuToggler" class="toggler__label">
 
 </label>
 <nav class="nav-content" role="navigation">
 <a href="https://www.python.org/" class="nav-logo">
 <img src="../_static/py.svg" alt="Logo"/>
 </a>
 <div class="version_switcher_placeholder"></div>
 <form role="search" class="search" action="../search.html" method="get">
 <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon">
 <path fill-rule="nonzero"
 d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z" fill="#444"></path>
 </svg>
 <input type="text" name="q" aria-label="Quick search"/>
 <input type="submit" value="Go"/>
 </form>
 </nav>
 <div class="menu-wrapper">
 <nav class="menu" role="navigation" aria-label="main navigation">
 <div class="language_switcher_placeholder"></div>
 <h3><a href="../contents.html">Table of Contents</a></h3>
 <ul>
<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate">collections.abc</code> — Abstract Base Classes for Containers</a><ul>
<li><a class="reference internal" href="#collections-abstract-base-classes">Collections Abstract Base Classes</a></li>
<li><a class="reference internal" href="#collections-abstract-base-classes-detailed-descriptions">Collections Abstract Base Classes – Detailed Descriptions</a></li>
<li><a class="reference internal" href="#examples-and-recipes">Examples and Recipes</a></li>
</ul>
</li>
</ul>

<div class="related" role="navigation" aria-label="related navigation">
 <h3>Navigation</h3>
 <ul>
 <li class="right" style="margin-right: 10px">
 <a href="../genindex.html" title="General Index"
 accesskey="I">index</a></li>
 <li class="right" >
 <a href="../py-modindex.html" title="Python Module Index"
 >modules</a> |</li>
 <li class="right" >
 <a href="heapq.html" title="heapq — Heap queue algorithm"
 accesskey="N">next</a> |</li>
 <li class="right" >
 <a href="collections.html" title="collections — Container datatypes"
 accesskey="P">previous</a> |</li>

<li><img src="../_static/py.svg" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li>
 <li><a href="https://www.python.org/">Python</a> &#187;</li>
 <li class="switchers">
 <div class="language_switcher_placeholder"></div>
 <div class="version_switcher_placeholder"></div>
 </li>
 <li>
 
 </li>
 <li id="cpython-language-and-version">
 <a href="../index.html">3.10.12 Documentation</a> &#187;
 </li>

<li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
 <li class="nav-item nav-item-2"><a href="datatypes.html" accesskey="U">Data Types</a> &#187;</li>
 <li class="nav-item nav-item-this"><a href=""><code class="xref py py-mod docutils literal notranslate">collections.abc</code> — Abstract Base Classes for Containers</a></li>
 <li class="right">

<div class="document">
 <div class="documentwrapper">
 <div class="bodywrapper">
 <div class="body" role="main">
 
 <section id="module-collections.abc">
<h1><a class="reference internal" href="#module-collections.abc" title="collections.abc: Abstract base classes for containers"><code class="xref py py-mod docutils literal notranslate">collections.abc</code></a> — Abstract Base Classes for Containers<a class="headerlink" href="#module-collections.abc" title="Permalink to this headline">¶</a></h1>
<div class="versionadded">
New in version 3.3: Formerly, this module was part of the <a class="reference internal" href="collections.html#module-collections" title="collections: Container datatypes"><code class="xref py py-mod docutils literal notranslate">collections</code></a> module.
</div>
Source code: <a class="reference external" href="https://github.com/python/cpython/tree/3.10/Lib/_collections_abc.py">Lib/_collections_abc.py</a>
<hr class="docutils" />
This module provides <a class="reference internal" href="../glossary.html#term-abstract-base-class">abstract base classes</a> that
can be used to test whether a class provides a particular interface; for
example, whether it is <a class="reference internal" href="../glossary.html#term-hashable">hashable</a> or whether it is a mapping.
An <a class="reference internal" href="functions.html#issubclass" title="issubclass"><code class="xref py py-func docutils literal notranslate">issubclass()</code></a> or <a class="reference internal" href="functions.html#isinstance" title="isinstance"><code class="xref py py-func docutils literal notranslate">isinstance()</code></a> test for an interface works in one
of three ways.
1) A newly written class can inherit directly from one of the
abstract base classes. The class must supply the required abstract
methods. The remaining mixin methods come from inheritance and can be
overridden if desired. Other methods may be added as needed:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class C(Sequence): # Direct inheritance
 def __init__(self): ... # Extra method not required by the ABC
 def __getitem__(self, index): ... # Required abstract method
 def __len__(self): ... # Required abstract method
 def count(self, value): ... # Optionally override a mixin method
</pre></div>
</div>
<div class="highlight-pycon3 notranslate"><div class="highlight"><pre>&gt;&gt;&gt; issubclass(C, Sequence)
True
&gt;&gt;&gt; isinstance(C(), Sequence)
True
</pre></div>
</div>
2) Existing classes and built-in classes can be registered as “virtual
subclasses” of the ABCs. Those classes should define the full API
including all of the abstract methods and all of the mixin methods.
This lets users rely on <a class="reference internal" href="functions.html#issubclass" title="issubclass"><code class="xref py py-func docutils literal notranslate">issubclass()</code></a> or <a class="reference internal" href="functions.html#isinstance" title="isinstance"><code class="xref py py-func docutils literal notranslate">isinstance()</code></a> tests
to determine whether the full interface is supported. The exception to
this rule is for methods that are automatically inferred from the rest
of the API:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class D: # No inheritance
 def __init__(self): ... # Extra method not required by the ABC
 def __getitem__(self, index): ... # Abstract method
 def __len__(self): ... # Abstract method
 def count(self, value): ... # Mixin method
 def index(self, value): ... # Mixin method

Sequence.register(D) # Register instead of inherit
</pre></div>
</div>
<div class="highlight-pycon3 notranslate"><div class="highlight"><pre>&gt;&gt;&gt; issubclass(D, Sequence)
True
&gt;&gt;&gt; isinstance(D(), Sequence)
True
</pre></div>
</div>
In this example, class <code class="xref py py-class docutils literal notranslate">D</code> does not need to define
<code class="docutils literal notranslate">__contains__</code>, <code class="docutils literal notranslate">__iter__</code>, and <code class="docutils literal notranslate">__reversed__</code> because the
<a class="reference internal" href="../reference/expressions.html#comparisons">in-operator</a>, the <a class="reference internal" href="../glossary.html#term-iterable">iteration</a>
logic, and the <a class="reference internal" href="functions.html#reversed" title="reversed"><code class="xref py py-func docutils literal notranslate">reversed()</code></a> function automatically fall back to
using <code class="docutils literal notranslate">__getitem__</code> and <code class="docutils literal notranslate">__len__</code>.
3) Some simple interfaces are directly recognizable by the presence of
the required methods (unless those methods have been set to
<a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate">None</code></a>):
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class E:
 def __iter__(self): ...
 def __next__(next): ...
</pre></div>
</div>
<div class="highlight-pycon3 notranslate"><div class="highlight"><pre>&gt;&gt;&gt; issubclass(E, Iterable)
True
&gt;&gt;&gt; isinstance(E(), Iterable)
True
</pre></div>
</div>
Complex interfaces do not support this last technique because an
interface is more than just the presence of method names. Interfaces
specify semantics and relationships between methods that cannot be
inferred solely from the presence of specific method names. For
example, knowing that a class supplies <code class="docutils literal notranslate">__getitem__</code>, <code class="docutils literal notranslate">__len__</code>, and
<code class="docutils literal notranslate">__iter__</code> is insufficient for distinguishing a <a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate">Sequence</code></a> from
a <a class="reference internal" href="#collections.abc.Mapping" title="collections.abc.Mapping"><code class="xref py py-class docutils literal notranslate">Mapping</code></a>.
<div class="versionadded">
New in version 3.9: These abstract classes now support <code class="docutils literal notranslate">[]</code>. See <a class="reference internal" href="stdtypes.html#types-genericalias">Generic Alias Type</a>
and <a class="pep reference external" href="https://www.python.org/dev/peps/pep-0585">PEP 585</a>.
</div>
<section id="collections-abstract-base-classes">
<h2>Collections Abstract Base Classes<a class="headerlink" href="#collections-abstract-base-classes" title="Permalink to this headline">¶</a></h2>
The collections module offers the following <a class="reference internal" href="../glossary.html#term-abstract-base-class">ABCs</a>:
<table class="docutils align-default">
<colgroup>
<col style="width: 24%" />
<col style="width: 17%" />
<col style="width: 18%" />
<col style="width: 41%" />
</colgroup>
<thead>
<tr class="row-odd"><th class="head">ABC</th>
<th class="head">Inherits from</th>
<th class="head">Abstract Methods</th>
<th class="head">Mixin Methods</th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.Container" title="collections.abc.Container"><code class="xref py py-class docutils literal notranslate">Container</code></a> <a class="footnote-reference brackets" href="#id17" id="id2">1</a></td>
<td></td>
<td><code class="docutils literal notranslate">__contains__</code></td>
<td></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.Hashable" title="collections.abc.Hashable"><code class="xref py py-class docutils literal notranslate">Hashable</code></a> <a class="footnote-reference brackets" href="#id17" id="id3">1</a></td>
<td></td>
<td><code class="docutils literal notranslate">__hash__</code></td>
<td></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate">Iterable</code></a> <a class="footnote-reference brackets" href="#id17" id="id4">1</a> <a class="footnote-reference brackets" href="#id18" id="id5">2</a></td>
<td></td>
<td><code class="docutils literal notranslate">__iter__</code></td>
<td></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.Iterator" title="collections.abc.Iterator"><code class="xref py py-class docutils literal notranslate">Iterator</code></a> <a class="footnote-reference brackets" href="#id17" id="id6">1</a></td>
<td><a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate">Iterable</code></a></td>
<td><code class="docutils literal notranslate">__next__</code></td>
<td><code class="docutils literal notranslate">__iter__</code></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.Reversible" title="collections.abc.Reversible"><code class="xref py py-class docutils literal notranslate">Reversible</code></a> <a class="footnote-reference brackets" href="#id17" id="id7">1</a></td>
<td><a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate">Iterable</code></a></td>
<td><code class="docutils literal notranslate">__reversed__</code></td>
<td></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.Generator" title="collections.abc.Generator"><code class="xref py py-class docutils literal notranslate">Generator</code></a> <a class="footnote-reference brackets" href="#id17" id="id8">1</a></td>
<td><a class="reference internal" href="#collections.abc.Iterator" title="collections.abc.Iterator"><code class="xref py py-class docutils literal notranslate">Iterator</code></a></td>
<td><code class="docutils literal notranslate">send</code>, <code class="docutils literal notranslate">throw</code></td>
<td><code class="docutils literal notranslate">close</code>, <code class="docutils literal notranslate">__iter__</code>, <code class="docutils literal notranslate">__next__</code></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.Sized" title="collections.abc.Sized"><code class="xref py py-class docutils literal notranslate">Sized</code></a> <a class="footnote-reference brackets" href="#id17" id="id9">1</a></td>
<td></td>
<td><code class="docutils literal notranslate">__len__</code></td>
<td></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.Callable" title="collections.abc.Callable"><code class="xref py py-class docutils literal notranslate">Callable</code></a> <a class="footnote-reference brackets" href="#id17" id="id10">1</a></td>
<td></td>
<td><code class="docutils literal notranslate">__call__</code></td>
<td></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.Collection" title="collections.abc.Collection"><code class="xref py py-class docutils literal notranslate">Collection</code></a> <a class="footnote-reference brackets" href="#id17" id="id11">1</a></td>
<td><a class="reference internal" href="#collections.abc.Sized" title="collections.abc.Sized"><code class="xref py py-class docutils literal notranslate">Sized</code></a>,
<a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate">Iterable</code></a>,
<a class="reference internal" href="#collections.abc.Container" title="collections.abc.Container"><code class="xref py py-class docutils literal notranslate">Container</code></a></td>
<td><code class="docutils literal notranslate">__contains__</code>,
<code class="docutils literal notranslate">__iter__</code>,
<code class="docutils literal notranslate">__len__</code></td>
<td></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate">Sequence</code></a></td>
<td><a class="reference internal" href="#collections.abc.Reversible" title="collections.abc.Reversible"><code class="xref py py-class docutils literal notranslate">Reversible</code></a>,
<a class="reference internal" href="#collections.abc.Collection" title="collections.abc.Collection"><code class="xref py py-class docutils literal notranslate">Collection</code></a></td>
<td><code class="docutils literal notranslate">__getitem__</code>,
<code class="docutils literal notranslate">__len__</code></td>
<td><code class="docutils literal notranslate">__contains__</code>, <code class="docutils literal notranslate">__iter__</code>, <code class="docutils literal notranslate">__reversed__</code>,
<code class="docutils literal notranslate">index</code>, and <code class="docutils literal notranslate">count</code></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.MutableSequence" title="collections.abc.MutableSequence"><code class="xref py py-class docutils literal notranslate">MutableSequence</code></a></td>
<td><a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate">Sequence</code></a></td>
<td><code class="docutils literal notranslate">__getitem__</code>,
<code class="docutils literal notranslate">__setitem__</code>,
<code class="docutils literal notranslate">__delitem__</code>,
<code class="docutils literal notranslate">__len__</code>,
<code class="docutils literal notranslate">insert</code></td>
<td>Inherited <a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate">Sequence</code></a> methods and
<code class="docutils literal notranslate">append</code>, <code class="docutils literal notranslate">reverse</code>, <code class="docutils literal notranslate">extend</code>, <code class="docutils literal notranslate">pop</code>,
<code class="docutils literal notranslate">remove</code>, and <code class="docutils literal notranslate">__iadd__</code></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.ByteString" title="collections.abc.ByteString"><code class="xref py py-class docutils literal notranslate">ByteString</code></a></td>
<td><a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate">Sequence</code></a></td>
<td><code class="docutils literal notranslate">__getitem__</code>,
<code class="docutils literal notranslate">__len__</code></td>
<td>Inherited <a class="reference internal" href="#collections.abc.Sequence" title="collections.abc.Sequence"><code class="xref py py-class docutils literal notranslate">Sequence</code></a> methods</td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate">Set</code></a></td>
<td><a class="reference internal" href="#collections.abc.Collection" title="collections.abc.Collection"><code class="xref py py-class docutils literal notranslate">Collection</code></a></td>
<td><code class="docutils literal notranslate">__contains__</code>,
<code class="docutils literal notranslate">__iter__</code>,
<code class="docutils literal notranslate">__len__</code></td>
<td><code class="docutils literal notranslate">__le__</code>, <code class="docutils literal notranslate">__lt__</code>, <code class="docutils literal notranslate">__eq__</code>, <code class="docutils literal notranslate">__ne__</code>,
<code class="docutils literal notranslate">__gt__</code>, <code class="docutils literal notranslate">__ge__</code>, <code class="docutils literal notranslate">__and__</code>, <code class="docutils literal notranslate">__or__</code>,
<code class="docutils literal notranslate">__sub__</code>, <code class="docutils literal notranslate">__xor__</code>, and <code class="docutils literal notranslate">isdisjoint</code></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.MutableSet" title="collections.abc.MutableSet"><code class="xref py py-class docutils literal notranslate">MutableSet</code></a></td>
<td><a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate">Set</code></a></td>
<td><code class="docutils literal notranslate">__contains__</code>,
<code class="docutils literal notranslate">__iter__</code>,
<code class="docutils literal notranslate">__len__</code>,
<code class="docutils literal notranslate">add</code>,
<code class="docutils literal notranslate">discard</code></td>
<td>Inherited <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate">Set</code></a> methods and
<code class="docutils literal notranslate">clear</code>, <code class="docutils literal notranslate">pop</code>, <code class="docutils literal notranslate">remove</code>, <code class="docutils literal notranslate">__ior__</code>,
<code class="docutils literal notranslate">__iand__</code>, <code class="docutils literal notranslate">__ixor__</code>, and <code class="docutils literal notranslate">__isub__</code></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.Mapping" title="collections.abc.Mapping"><code class="xref py py-class docutils literal notranslate">Mapping</code></a></td>
<td><a class="reference internal" href="#collections.abc.Collection" title="collections.abc.Collection"><code class="xref py py-class docutils literal notranslate">Collection</code></a></td>
<td><code class="docutils literal notranslate">__getitem__</code>,
<code class="docutils literal notranslate">__iter__</code>,
<code class="docutils literal notranslate">__len__</code></td>
<td><code class="docutils literal notranslate">__contains__</code>, <code class="docutils literal notranslate">keys</code>, <code class="docutils literal notranslate">items</code>, <code class="docutils literal notranslate">values</code>,
<code class="docutils literal notranslate">get</code>, <code class="docutils literal notranslate">__eq__</code>, and <code class="docutils literal notranslate">__ne__</code></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.MutableMapping" title="collections.abc.MutableMapping"><code class="xref py py-class docutils literal notranslate">MutableMapping</code></a></td>
<td><a class="reference internal" href="#collections.abc.Mapping" title="collections.abc.Mapping"><code class="xref py py-class docutils literal notranslate">Mapping</code></a></td>
<td><code class="docutils literal notranslate">__getitem__</code>,
<code class="docutils literal notranslate">__setitem__</code>,
<code class="docutils literal notranslate">__delitem__</code>,
<code class="docutils literal notranslate">__iter__</code>,
<code class="docutils literal notranslate">__len__</code></td>
<td>Inherited <a class="reference internal" href="#collections.abc.Mapping" title="collections.abc.Mapping"><code class="xref py py-class docutils literal notranslate">Mapping</code></a> methods and
<code class="docutils literal notranslate">pop</code>, <code class="docutils literal notranslate">popitem</code>, <code class="docutils literal notranslate">clear</code>, <code class="docutils literal notranslate">update</code>,
and <code class="docutils literal notranslate">setdefault</code></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.MappingView" title="collections.abc.MappingView"><code class="xref py py-class docutils literal notranslate">MappingView</code></a></td>
<td><a class="reference internal" href="#collections.abc.Sized" title="collections.abc.Sized"><code class="xref py py-class docutils literal notranslate">Sized</code></a></td>
<td></td>
<td><code class="docutils literal notranslate">__len__</code></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.ItemsView" title="collections.abc.ItemsView"><code class="xref py py-class docutils literal notranslate">ItemsView</code></a></td>
<td><a class="reference internal" href="#collections.abc.MappingView" title="collections.abc.MappingView"><code class="xref py py-class docutils literal notranslate">MappingView</code></a>,
<a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate">Set</code></a></td>
<td></td>
<td><code class="docutils literal notranslate">__contains__</code>,
<code class="docutils literal notranslate">__iter__</code></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.KeysView" title="collections.abc.KeysView"><code class="xref py py-class docutils literal notranslate">KeysView</code></a></td>
<td><a class="reference internal" href="#collections.abc.MappingView" title="collections.abc.MappingView"><code class="xref py py-class docutils literal notranslate">MappingView</code></a>,
<a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate">Set</code></a></td>
<td></td>
<td><code class="docutils literal notranslate">__contains__</code>,
<code class="docutils literal notranslate">__iter__</code></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.ValuesView" title="collections.abc.ValuesView"><code class="xref py py-class docutils literal notranslate">ValuesView</code></a></td>
<td><a class="reference internal" href="#collections.abc.MappingView" title="collections.abc.MappingView"><code class="xref py py-class docutils literal notranslate">MappingView</code></a>,
<a class="reference internal" href="#collections.abc.Collection" title="collections.abc.Collection"><code class="xref py py-class docutils literal notranslate">Collection</code></a></td>
<td></td>
<td><code class="docutils literal notranslate">__contains__</code>, <code class="docutils literal notranslate">__iter__</code></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.Awaitable" title="collections.abc.Awaitable"><code class="xref py py-class docutils literal notranslate">Awaitable</code></a> <a class="footnote-reference brackets" href="#id17" id="id12">1</a></td>
<td></td>
<td><code class="docutils literal notranslate">__await__</code></td>
<td></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.Coroutine" title="collections.abc.Coroutine"><code class="xref py py-class docutils literal notranslate">Coroutine</code></a> <a class="footnote-reference brackets" href="#id17" id="id13">1</a></td>
<td><a class="reference internal" href="#collections.abc.Awaitable" title="collections.abc.Awaitable"><code class="xref py py-class docutils literal notranslate">Awaitable</code></a></td>
<td><code class="docutils literal notranslate">send</code>, <code class="docutils literal notranslate">throw</code></td>
<td><code class="docutils literal notranslate">close</code></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.AsyncIterable" title="collections.abc.AsyncIterable"><code class="xref py py-class docutils literal notranslate">AsyncIterable</code></a> <a class="footnote-reference brackets" href="#id17" id="id14">1</a></td>
<td></td>
<td><code class="docutils literal notranslate">__aiter__</code></td>
<td></td>
</tr>
<tr class="row-odd"><td><a class="reference internal" href="#collections.abc.AsyncIterator" title="collections.abc.AsyncIterator"><code class="xref py py-class docutils literal notranslate">AsyncIterator</code></a> <a class="footnote-reference brackets" href="#id17" id="id15">1</a></td>
<td><a class="reference internal" href="#collections.abc.AsyncIterable" title="collections.abc.AsyncIterable"><code class="xref py py-class docutils literal notranslate">AsyncIterable</code></a></td>
<td><code class="docutils literal notranslate">__anext__</code></td>
<td><code class="docutils literal notranslate">__aiter__</code></td>
</tr>
<tr class="row-even"><td><a class="reference internal" href="#collections.abc.AsyncGenerator" title="collections.abc.AsyncGenerator"><code class="xref py py-class docutils literal notranslate">AsyncGenerator</code></a> <a class="footnote-reference brackets" href="#id17" id="id16">1</a></td>
<td><a class="reference internal" href="#collections.abc.AsyncIterator" title="collections.abc.AsyncIterator"><code class="xref py py-class docutils literal notranslate">AsyncIterator</code></a></td>
<td><code class="docutils literal notranslate">asend</code>, <code class="docutils literal notranslate">athrow</code></td>
<td><code class="docutils literal notranslate">aclose</code>, <code class="docutils literal notranslate">__aiter__</code>, <code class="docutils literal notranslate">__anext__</code></td>
</tr>
</tbody>
</table>
Footnotes
<dl class="footnote brackets">
<dt class="label" id="id17">1(<a href="#id2">1</a>,<a href="#id3">2</a>,<a href="#id4">3</a>,<a href="#id6">4</a>,<a href="#id7">5</a>,<a href="#id8">6</a>,<a href="#id9">7</a>,<a href="#id10">8</a>,<a href="#id11">9</a>,<a href="#id12">10</a>,<a href="#id13">11</a>,<a href="#id14">12</a>,<a href="#id15">13</a>,<a href="#id16">14</a>)</dt>
<dd>These ABCs override <code class="xref py py-meth docutils literal notranslate">object.__subclasshook__()</code> to support
testing an interface by verifying the required methods are present
and have not been set to <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate">None</code></a>. This only works for simple
interfaces. More complex interfaces require registration or direct
subclassing.
</dd>
<dt class="label" id="id18"><a class="fn-backref" href="#id5">2</a></dt>
<dd>Checking <code class="docutils literal notranslate">isinstance(obj, Iterable)</code> detects classes that are
registered as <a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate">Iterable</code></a> or that have an <code class="xref py py-meth docutils literal notranslate">__iter__()</code>
method, but it does not detect classes that iterate with the
<code class="xref py py-meth docutils literal notranslate">__getitem__()</code> method. The only reliable way to determine
whether an object is <a class="reference internal" href="../glossary.html#term-iterable">iterable</a> is to call <code class="docutils literal notranslate">iter(obj)</code>.
</dd>
</dl>
</section>
<section id="collections-abstract-base-classes-detailed-descriptions">
<h2>Collections Abstract Base Classes – Detailed Descriptions<a class="headerlink" href="#collections-abstract-base-classes-detailed-descriptions" title="Permalink to this headline">¶</a></h2>
<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Container">
class collections.abc.Container<a class="headerlink" href="#collections.abc.Container" title="Permalink to this definition">¶</a></dt>
<dd>ABC for classes that provide the <code class="xref py py-meth docutils literal notranslate">__contains__()</code> method.
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Hashable">
class collections.abc.Hashable<a class="headerlink" href="#collections.abc.Hashable" title="Permalink to this definition">¶</a></dt>
<dd>ABC for classes that provide the <code class="xref py py-meth docutils literal notranslate">__hash__()</code> method.
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Sized">
class collections.abc.Sized<a class="headerlink" href="#collections.abc.Sized" title="Permalink to this definition">¶</a></dt>
<dd>ABC for classes that provide the <code class="xref py py-meth docutils literal notranslate">__len__()</code> method.
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Callable">
class collections.abc.Callable<a class="headerlink" href="#collections.abc.Callable" title="Permalink to this definition">¶</a></dt>
<dd>ABC for classes that provide the <code class="xref py py-meth docutils literal notranslate">__call__()</code> method.
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Iterable">
class collections.abc.Iterable<a class="headerlink" href="#collections.abc.Iterable" title="Permalink to this definition">¶</a></dt>
<dd>ABC for classes that provide the <code class="xref py py-meth docutils literal notranslate">__iter__()</code> method.
Checking <code class="docutils literal notranslate">isinstance(obj, Iterable)</code> detects classes that are registered
as <a class="reference internal" href="#collections.abc.Iterable" title="collections.abc.Iterable"><code class="xref py py-class docutils literal notranslate">Iterable</code></a> or that have an <code class="xref py py-meth docutils literal notranslate">__iter__()</code> method, but it does
not detect classes that iterate with the <code class="xref py py-meth docutils literal notranslate">__getitem__()</code> method.
The only reliable way to determine whether an object is <a class="reference internal" href="../glossary.html#term-iterable">iterable</a>
is to call <code class="docutils literal notranslate">iter(obj)</code>.
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Collection">
class collections.abc.Collection<a class="headerlink" href="#collections.abc.Collection" title="Permalink to this definition">¶</a></dt>
<dd>ABC for sized iterable container classes.
<div class="versionadded">
New in version 3.6.
</div>
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Iterator">
class collections.abc.Iterator<a class="headerlink" href="#collections.abc.Iterator" title="Permalink to this definition">¶</a></dt>
<dd>ABC for classes that provide the <a class="reference internal" href="stdtypes.html#iterator.__iter__" title="iterator.__iter__"><code class="xref py py-meth docutils literal notranslate">__iter__()</code></a> and
<a class="reference internal" href="stdtypes.html#iterator.__next__" title="iterator.__next__"><code class="xref py py-meth docutils literal notranslate">__next__()</code></a> methods. See also the definition of
<a class="reference internal" href="../glossary.html#term-iterator">iterator</a>.
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Reversible">
class collections.abc.Reversible<a class="headerlink" href="#collections.abc.Reversible" title="Permalink to this definition">¶</a></dt>
<dd>ABC for iterable classes that also provide the <code class="xref py py-meth docutils literal notranslate">__reversed__()</code>
method.
<div class="versionadded">
New in version 3.6.
</div>
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Generator">
class collections.abc.Generator<a class="headerlink" href="#collections.abc.Generator" title="Permalink to this definition">¶</a></dt>
<dd>ABC for generator classes that implement the protocol defined in
<a class="pep reference external" href="https://www.python.org/dev/peps/pep-0342">PEP 342</a> that extends iterators with the <a class="reference internal" href="../reference/expressions.html#generator.send" title="generator.send"><code class="xref py py-meth docutils literal notranslate">send()</code></a>,
<a class="reference internal" href="../reference/expressions.html#generator.throw" title="generator.throw"><code class="xref py py-meth docutils literal notranslate">throw()</code></a> and <a class="reference internal" href="../reference/expressions.html#generator.close" title="generator.close"><code class="xref py py-meth docutils literal notranslate">close()</code></a> methods.
See also the definition of <a class="reference internal" href="../glossary.html#term-generator">generator</a>.
<div class="versionadded">
New in version 3.5.
</div>
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Sequence">
class collections.abc.Sequence<a class="headerlink" href="#collections.abc.Sequence" title="Permalink to this definition">¶</a></dt>
<dt class="sig sig-object py" id="collections.abc.MutableSequence">
class collections.abc.MutableSequence<a class="headerlink" href="#collections.abc.MutableSequence" title="Permalink to this definition">¶</a></dt>
<dt class="sig sig-object py" id="collections.abc.ByteString">
class collections.abc.ByteString<a class="headerlink" href="#collections.abc.ByteString" title="Permalink to this definition">¶</a></dt>
<dd>ABCs for read-only and mutable <a class="reference internal" href="../glossary.html#term-sequence">sequences</a>.
Implementation note: Some of the mixin methods, such as
<code class="xref py py-meth docutils literal notranslate">__iter__()</code>, <code class="xref py py-meth docutils literal notranslate">__reversed__()</code> and <code class="xref py py-meth docutils literal notranslate">index()</code>, make
repeated calls to the underlying <code class="xref py py-meth docutils literal notranslate">__getitem__()</code> method.
Consequently, if <code class="xref py py-meth docutils literal notranslate">__getitem__()</code> is implemented with constant
access speed, the mixin methods will have linear performance;
however, if the underlying method is linear (as it would be with a
linked list), the mixins will have quadratic performance and will
likely need to be overridden.
<div class="versionchanged">
Changed in version 3.5: The index() method added support for stop and start
arguments.
</div>
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Set">
class collections.abc.Set<a class="headerlink" href="#collections.abc.Set" title="Permalink to this definition">¶</a></dt>
<dt class="sig sig-object py" id="collections.abc.MutableSet">
class collections.abc.MutableSet<a class="headerlink" href="#collections.abc.MutableSet" title="Permalink to this definition">¶</a></dt>
<dd>ABCs for read-only and mutable sets.
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Mapping">
class collections.abc.Mapping<a class="headerlink" href="#collections.abc.Mapping" title="Permalink to this definition">¶</a></dt>
<dt class="sig sig-object py" id="collections.abc.MutableMapping">
class collections.abc.MutableMapping<a class="headerlink" href="#collections.abc.MutableMapping" title="Permalink to this definition">¶</a></dt>
<dd>ABCs for read-only and mutable <a class="reference internal" href="../glossary.html#term-mapping">mappings</a>.
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.MappingView">
class collections.abc.MappingView<a class="headerlink" href="#collections.abc.MappingView" title="Permalink to this definition">¶</a></dt>
<dt class="sig sig-object py" id="collections.abc.ItemsView">
class collections.abc.ItemsView<a class="headerlink" href="#collections.abc.ItemsView" title="Permalink to this definition">¶</a></dt>
<dt class="sig sig-object py" id="collections.abc.KeysView">
class collections.abc.KeysView<a class="headerlink" href="#collections.abc.KeysView" title="Permalink to this definition">¶</a></dt>
<dt class="sig sig-object py" id="collections.abc.ValuesView">
class collections.abc.ValuesView<a class="headerlink" href="#collections.abc.ValuesView" title="Permalink to this definition">¶</a></dt>
<dd>ABCs for mapping, items, keys, and values <a class="reference internal" href="../glossary.html#term-dictionary-view">views</a>.
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Awaitable">
class collections.abc.Awaitable<a class="headerlink" href="#collections.abc.Awaitable" title="Permalink to this definition">¶</a></dt>
<dd>ABC for <a class="reference internal" href="../glossary.html#term-awaitable">awaitable</a> objects, which can be used in <a class="reference internal" href="../reference/expressions.html#await"><code class="xref std std-keyword docutils literal notranslate">await</code></a>
expressions. Custom implementations must provide the <code class="xref py py-meth docutils literal notranslate">__await__()</code>
method.
<a class="reference internal" href="../glossary.html#term-coroutine">Coroutine</a> objects and instances of the
<a class="reference internal" href="#collections.abc.Coroutine" title="collections.abc.Coroutine"><code class="xref py py-class docutils literal notranslate">Coroutine</code></a> ABC are all instances of this ABC.
<div class="admonition note">
Note
In CPython, generator-based coroutines (generators decorated with
<a class="reference internal" href="types.html#types.coroutine" title="types.coroutine"><code class="xref py py-func docutils literal notranslate">types.coroutine()</code></a> or <a class="reference internal" href="asyncio-task.html#asyncio.coroutine" title="asyncio.coroutine"><code class="xref py py-func docutils literal notranslate">asyncio.coroutine()</code></a>) are
awaitables, even though they do not have an <code class="xref py py-meth docutils literal notranslate">__await__()</code> method.
Using <code class="docutils literal notranslate">isinstance(gencoro, Awaitable)</code> for them will return <code class="docutils literal notranslate">False</code>.
Use <a class="reference internal" href="inspect.html#inspect.isawaitable" title="inspect.isawaitable"><code class="xref py py-func docutils literal notranslate">inspect.isawaitable()</code></a> to detect them.
</div>
<div class="versionadded">
New in version 3.5.
</div>
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.Coroutine">
class collections.abc.Coroutine<a class="headerlink" href="#collections.abc.Coroutine" title="Permalink to this definition">¶</a></dt>
<dd>ABC for coroutine compatible classes. These implement the
following methods, defined in <a class="reference internal" href="../reference/datamodel.html#coroutine-objects">Coroutine Objects</a>:
<a class="reference internal" href="../reference/datamodel.html#coroutine.send" title="coroutine.send"><code class="xref py py-meth docutils literal notranslate">send()</code></a>, <a class="reference internal" href="../reference/datamodel.html#coroutine.throw" title="coroutine.throw"><code class="xref py py-meth docutils literal notranslate">throw()</code></a>, and
<a class="reference internal" href="../reference/datamodel.html#coroutine.close" title="coroutine.close"><code class="xref py py-meth docutils literal notranslate">close()</code></a>. Custom implementations must also implement
<code class="xref py py-meth docutils literal notranslate">__await__()</code>. All <a class="reference internal" href="#collections.abc.Coroutine" title="collections.abc.Coroutine"><code class="xref py py-class docutils literal notranslate">Coroutine</code></a> instances are also instances of
<a class="reference internal" href="#collections.abc.Awaitable" title="collections.abc.Awaitable"><code class="xref py py-class docutils literal notranslate">Awaitable</code></a>. See also the definition of <a class="reference internal" href="../glossary.html#term-coroutine">coroutine</a>.
<div class="admonition note">
Note
In CPython, generator-based coroutines (generators decorated with
<a class="reference internal" href="types.html#types.coroutine" title="types.coroutine"><code class="xref py py-func docutils literal notranslate">types.coroutine()</code></a> or <a class="reference internal" href="asyncio-task.html#asyncio.coroutine" title="asyncio.coroutine"><code class="xref py py-func docutils literal notranslate">asyncio.coroutine()</code></a>) are
awaitables, even though they do not have an <code class="xref py py-meth docutils literal notranslate">__await__()</code> method.
Using <code class="docutils literal notranslate">isinstance(gencoro, Coroutine)</code> for them will return <code class="docutils literal notranslate">False</code>.
Use <a class="reference internal" href="inspect.html#inspect.isawaitable" title="inspect.isawaitable"><code class="xref py py-func docutils literal notranslate">inspect.isawaitable()</code></a> to detect them.
</div>
<div class="versionadded">
New in version 3.5.
</div>
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.AsyncIterable">
class collections.abc.AsyncIterable<a class="headerlink" href="#collections.abc.AsyncIterable" title="Permalink to this definition">¶</a></dt>
<dd>ABC for classes that provide <code class="docutils literal notranslate">__aiter__</code> method. See also the
definition of <a class="reference internal" href="../glossary.html#term-asynchronous-iterable">asynchronous iterable</a>.
<div class="versionadded">
New in version 3.5.
</div>
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.AsyncIterator">
class collections.abc.AsyncIterator<a class="headerlink" href="#collections.abc.AsyncIterator" title="Permalink to this definition">¶</a></dt>
<dd>ABC for classes that provide <code class="docutils literal notranslate">__aiter__</code> and <code class="docutils literal notranslate">__anext__</code>
methods. See also the definition of <a class="reference internal" href="../glossary.html#term-asynchronous-iterator">asynchronous iterator</a>.
<div class="versionadded">
New in version 3.5.
</div>
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="collections.abc.AsyncGenerator">
class collections.abc.AsyncGenerator<a class="headerlink" href="#collections.abc.AsyncGenerator" title="Permalink to this definition">¶</a></dt>
<dd>ABC for asynchronous generator classes that implement the protocol
defined in <a class="pep reference external" href="https://www.python.org/dev/peps/pep-0525">PEP 525</a> and <a class="pep reference external" href="https://www.python.org/dev/peps/pep-0492">PEP 492</a>.
<div class="versionadded">
New in version 3.6.
</div>
</dd></dl>

</section>
<section id="examples-and-recipes">
<h2>Examples and Recipes<a class="headerlink" href="#examples-and-recipes" title="Permalink to this headline">¶</a></h2>
ABCs allow us to ask classes or instances if they provide
particular functionality, for example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>size = None
if isinstance(myvar, collections.abc.Sized):
 size = len(myvar)
</pre></div>
</div>
Several of the ABCs are also useful as mixins that make it easier to develop
classes supporting container APIs. For example, to write a class supporting
the full <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate">Set</code></a> API, it is only necessary to supply the three underlying
abstract methods: <code class="xref py py-meth docutils literal notranslate">__contains__()</code>, <code class="xref py py-meth docutils literal notranslate">__iter__()</code>, and <code class="xref py py-meth docutils literal notranslate">__len__()</code>.
The ABC supplies the remaining methods such as <code class="xref py py-meth docutils literal notranslate">__and__()</code> and
<code class="xref py py-meth docutils literal notranslate">isdisjoint()</code>:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class ListBasedSet(collections.abc.Set):
 &#39;&#39;&#39; Alternate set implementation favoring space over speed
 and not requiring the set elements to be hashable. &#39;&#39;&#39;
 def __init__(self, iterable):
 self.elements = lst = []
 for value in iterable:
 if value not in lst:
 lst.append(value)

def __iter__(self):
 return iter(self.elements)

def __contains__(self, value):
 return value in self.elements

def __len__(self):
 return len(self.elements)

s1 = ListBasedSet(&#39;abcdef&#39;)
s2 = ListBasedSet(&#39;defghi&#39;)
overlap = s1 &amp; s2 # The __and__() method is supported automatically
</pre></div>
</div>
Notes on using <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate">Set</code></a> and <a class="reference internal" href="#collections.abc.MutableSet" title="collections.abc.MutableSet"><code class="xref py py-class docutils literal notranslate">MutableSet</code></a> as a mixin:
<ol class="arabic simple">
<li>Since some set operations create new sets, the default mixin methods need
a way to create new instances from an iterable. The class constructor is
assumed to have a signature in the form <code class="docutils literal notranslate">ClassName(iterable)</code>.
That assumption is factored-out to an internal classmethod called
<code class="xref py py-meth docutils literal notranslate">_from_iterable()</code> which calls <code class="docutils literal notranslate">cls(iterable)</code> to produce a new set.
If the <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate">Set</code></a> mixin is being used in a class with a different
constructor signature, you will need to override <code class="xref py py-meth docutils literal notranslate">_from_iterable()</code>
with a classmethod or regular method that can construct new instances from
an iterable argument.</li>
<li>To override the comparisons (presumably for speed, as the
semantics are fixed), redefine <code class="xref py py-meth docutils literal notranslate">__le__()</code> and <code class="xref py py-meth docutils literal notranslate">__ge__()</code>,
then the other operations will automatically follow suit.</li>
<li>The <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-class docutils literal notranslate">Set</code></a> mixin provides a <code class="xref py py-meth docutils literal notranslate">_hash()</code> method to compute a hash value
for the set; however, <code class="xref py py-meth docutils literal notranslate">__hash__()</code> is not defined because not all sets
are <a class="reference internal" href="../glossary.html#term-hashable">hashable</a> or immutable. To add set hashability using mixins,
inherit from both <a class="reference internal" href="#collections.abc.Set" title="collections.abc.Set"><code class="xref py py-meth docutils literal notranslate">Set()</code></a> and <a class="reference internal" href="#collections.abc.Hashable" title="collections.abc.Hashable"><code class="xref py py-meth docutils literal notranslate">Hashable()</code></a>, then define
<code class="docutils literal notranslate">__hash__ = Set._hash</code>.</li>
</ol>
<div class="admonition seealso">
See also
<ul class="simple">
<li><a class="reference external" href="https://code.activestate.com/recipes/576694/">OrderedSet recipe</a> for an
example built on <a class="reference internal" href="#collections.abc.MutableSet" title="collections.abc.MutableSet"><code class="xref py py-class docutils literal notranslate">MutableSet</code></a>.</li>
<li>For more about ABCs, see the <a class="reference internal" href="abc.html#module-abc" title="abc: Abstract base classes according to :pep:`3119`."><code class="xref py py-mod docutils literal notranslate">abc</code></a> module and <a class="pep reference external" href="https://www.python.org/dev/peps/pep-3119">PEP 3119</a>.</li>
</ul>
</div>
</section>
</section>

<div class="clearer"></div>
 </div>
 </div>
 </div>
 <div class="sphinxsidebar" role="navigation" aria-label="main navigation">
 <div class="sphinxsidebarwrapper">
 <h3><a href="../contents.html">Table of Contents</a></h3>
 <ul>
<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate">collections.abc</code> — Abstract Base Classes for Containers</a><ul>
<li><a class="reference internal" href="#collections-abstract-base-classes">Collections Abstract Base Classes</a></li>
<li><a class="reference internal" href="#collections-abstract-base-classes-detailed-descriptions">Collections Abstract Base Classes – Detailed Descriptions</a></li>
<li><a class="reference internal" href="#examples-and-recipes">Examples and Recipes</a></li>
</ul>
</li>
</ul>

<h4>Previous topic</h4>
 <a href="collections.html"
 title="previous chapter"><code class="xref py py-mod docutils literal notranslate">collections</code> — Container datatypes</a>
 <h4>Next topic</h4>
 <a href="heapq.html"
 title="next chapter"><code class="xref py py-mod docutils literal notranslate">heapq</code> — Heap queue algorithm</a>
 <div role="note" aria-label="source link">
 <h3>This Page</h3>
 <ul class="this-page-menu">
 <li><a href="../bugs.html">Report a Bug</a></li>
 <li>
 <a href="https://github.com/python/cpython/blob/3.10/Doc/library/collections.abc.rst"
 rel="nofollow">Show Source
 </a>
 </li>
 </ul>
 </div>
 </div>
 </div>
 <div class="clearer"></div>
 </div> 
 <div class="related" role="navigation" aria-label="related navigation">
 <h3>Navigation</h3>
 <ul>
 <li class="right" style="margin-right: 10px">
 <a href="../genindex.html" title="General Index"
 >index</a></li>
 <li class="right" >
 <a href="../py-modindex.html" title="Python Module Index"
 >modules</a> |</li>
 <li class="right" >
 <a href="heapq.html" title="heapq — Heap queue algorithm"
 >next</a> |</li>
 <li class="right" >
 <a href="collections.html" title="collections — Container datatypes"
 >previous</a> |</li>

<li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
 <li class="nav-item nav-item-2"><a href="datatypes.html" >Data Types</a> &#187;</li>
 <li class="nav-item nav-item-this"><a href=""><code class="xref py py-mod docutils literal notranslate">collections.abc</code> — Abstract Base Classes for Containers</a></li>
 <li class="right">

<div class="inline-search" role="search">
 <form class="inline-search" action="../search.html" method="get">
 <input placeholder="Quick search" aria-label="Quick search" type="text" name="q" />
 <input type="submit" value="Go" />
 <input type="hidden" name="check_keywords" value="yes" />
 <input type="hidden" name="area" value="default" />
 </form>
 </div>
 |
 </li>
 
 </ul>
 </div> 
 <div class="footer">
 &copy; <a href="../copyright.html">Copyright</a> 2001-2026, Python Software Foundation.
 
 This page is licensed under the Python Software Foundation License Version 2.
 
 Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
 
 See <a href="/license.html">History and License</a> for more information.

The Python Software Foundation is a non-profit corporation.
<a href="https://www.python.org/psf/donations/">Please donate.</a>

Last updated on January 26, 2026.
 <a href="/bugs.html">Found a bug</a>?

Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 4.3.2.
 </div>

</body>
</html>

${this.title}

Code Editor : collections.abc.html