C:\Users\wusong>python Python 3.8.2rc1 (tags/v3.8.2rc1:8623e68, Feb 11 2020, 10:46:21) [MSC v.1916 64 bit (AMD64)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>>
输入help()
>>> help Type help() for interactive help, or help(object) for help about object. >>> help() Welcome to Python 3.8's help utility! If this is your first time using Python, you should definitely check out the tutorial on the Internet at https://docs.python.org/3.8/tutorial/. Enter the name of any module, keyword, or topic to get help on writing Python programs and using Python modules. To quit this help utility and return to the interpreter, just type "quit". To get a list of available modules, keywords, symbols, or topics, type "modules", "keywords", "symbols", or "topics". Each module also comes with a one-line summary of what it does; to list the modules whose name or summary contain a given string such as "spam", type "modules spam". help>
这句话：To get a list of available modules, keywords, symbols, or topics, type "modules", "keywords", "symbols", or "topics".
意思就是：
要获取可用模块、关键字、符号或主题的列表，请键入 “模块”、“关键字”、“符号”或“主题”。
我们先看下modules
在help模式下输入：modules
help> modules Please wait a moment while I gather a list of all available modules... D:\software_install\python\lib\pkgutil.py:92: UserWarning: The numpy.array_api submodule is still experimental. See NEP 47. __import__(info.name) PIL asyncpg idna selenium PyInstaller atexit imaplib serial PyQt5 atlastk imghdr setuptools __future__ attr imp shelve _abc attrs importlib shlex _ast audioop inspect shutil _asyncio backports io signal _bisect base64 ipaddress simplejson _blake2 bcrypt itertools site _bootlocale bdb jinja2 six _bz2 billiard json smtpd _cffi_backend binascii keyword smtplib _codecs binhex kiwisolver sndhdr _codecs_cn bisect kombu sniffio _codecs_hk broadcaster lib2to3 socket _codecs_iso2022 builtins libfuturize socketserver _codecs_jp bz2 libpasteurize socks _codecs_kr cProfile linecache sockshandler _codecs_tw calendar locale sortedcontainers _collections celery logging sqlalchemy _collections_abc certifi loguru sqlite3 _compat_pickle cffi lzma sqlparse _compression cgi mailbox sre_compile _contextvars cgitb mailcap sre_constants _csv charset_normalizer markupsafe sre_parse _ctypes chunk marshal ssl _ctypes_test click math starlette _datetime click_didyoumean matplotlib stat _decimal click_plugins mimetypes statistics _dummy_thread click_repl mmap string _elementtree cmath modulefinder stringprep _functools cmd msilib struct _hashlib code msvcrt subprocess _heapq codecs multiprocessing sunau _imp codeop nacl symbol _io collections netrc symtable _json colorama nntplib sys _locale colorsys nt sysconfig _lsprof compileall ntpath tabnanny _lzma concurrent nturl2path tarfile _markupbase configparser numbers telnetlib _md5 contextlib numpy tempfile _msi contextvars opcode test _multibytecodec contourpy operator textwrap _multiprocessing copy optparse tftpy _opcode copyreg ordered_set this _operator crypt ordlookup threading _osx_support cryptography os time _overlapped csv outcome timeit _pickle ctypes packaging tkinter _py_abc curses paramiko token _pydecimal cv2 parser tokenize _pyinstaller_hooks_contrib cycler past tortoise _pyio databases pathlib trace _queue dataclasses pdb traceback _random datetime pefile tracemalloc _ruamel_yaml dateutil peutils trio _sha1 dbm pickle trio_websocket _sha256 decimal pickletools tty _sha3 deepdiff pip turtle _sha512 difflib pipes turtledemo _signal dis pkg_resources types _sitebuiltins distlib pkgutil typing _socket distutils platform typing_extensions _sqlite3 django platformdirs tzdata _sre doctest plistlib unicodedata _ssl dotenv poplib unittest _stat dummy_threading posixpath urllib _statistics easy_install pprint urllib3 _string email prettytable uu _strptime encodings profile uuid _struct ensurepip prompt_toolkit uvicorn _symtable enum pstats venv _testbuffer errno psutil vine _testcapi fastapi pty virtualenv _testconsole faulthandler py_compile warnings _testimportmultiple filecmp pyclbr watchfiles _testmultiphase fileinput pycparser wave _thread filelock pydantic wcwidth _threading_local fnmatch pydoc weakref _tkinter fontTools pydoc_data webbrowser _tracemalloc formatter pyecharts websockets _warnings fractions pyexpat win32_setctime _weakref ftplib pylab win32ctypes _weakrefset functools pyparsing winreg _winapi future pyqt5_plugins winsound _xxsubinterpreters gc pyqt5_tools wsgiref _yaml genericpath pytz wsproto abc getopt qt5_applications xdrlib aifc getpass qt5_tools xlrd altgraph gettext queue xlwt amqp glob quopri xml antigravity greenlet random xmlrpc anyio gzip re xxsubtype argparse h21 reprlib yaml array hashlib requests zipapp asgiref heapq rlcompleter zipfile ast hmac runpy zipimport async_generator html sched zlib asynchat http secrets asyncio httptools select asyncore idlelib selectors Enter any module name to get more help. Or, type "modules spam" to search for modules whose name or summary contain the string "spam". help>
从这里可以看出还是有相当多的模块，比如我们常用的re,xlrd当然也有我们后期安装的；挑一个进去看看，有啥风景，就挑xlrd
help> xlrd Help on package xlrd: NAME xlrd DESCRIPTION # Copyright (c) 2005-2012 Stephen John Machin, Lingfo Pty Ltd # This module is part of the xlrd package, which is released under a # BSD-style licence. PACKAGE CONTENTS biffh book compdoc formatting formula info sheet timemachine xldate FUNCTIONS count_records(filename, outfile=<colorama.ansitowin32.StreamWrapper object at 0x000001D26AC13D00>) For debugging and analysis: summarise the file's BIFF records. ie: produce a sorted file of ``(record_name, count)``. :param filename: The path to the file to be summarised. :param outfile: An open file, to which the summary is written. -- More -- 行数:
这里面会详细介绍xlrd模块的名字，描述，模块目录、功能、版本、文件位置等信息，在最后一行看到-- More -- ，这是一个分页符，表示当前页面不能全部显示所有信息，需要部分分页操作，可以使用空格键切换下一页，也可以使用回车键看下一行，看你自己的需求进行操作，如果不想看了可输入q退出阅读模式，进入help模式，再输入q则可以继续退出help模式；
help> q
You are now leaving help and returning to the Python interpreter.
If you want to ask for help on a particular object directly from the
interpreter, you can type "help(object)". Executing "help('string')"
has the same effect as typing a particular string at the help> prompt.
>>>再看下我们后面会常说的关键字
help> keywords Here is a list of the Python keywords. Enter any keyword to get more help. False class from or None continue global pass True def if raise and del import return as elif in try assert else is while async except lambda with await finally nonlocal yield break for not
这个是罗列了我们在python语言中涉及的运算符
help> symbols Here is a list of the punctuation symbols which Python assigns special meaning to. Enter any symbol to get more help. != + <= __ " += <> ` """ , == b" % - > b' %= -= >= f" & . >> f' &= ... >>= j ' / @ r" ''' // J r' ( //= [ u" ) /= \ u' * : ] | ** < ^ |= **= << ^= ~ *= <<= _
