Python 3 - REPL

Updated: 2018-12-09

Starting REPL

$ python3
Python 3.5.1 (default, Apr  5 2016, 09:34:03)
[GCC 4.2.1 Compatible Apple LLVM 7.3.0 (clang-703.0.29)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>

Having Fun

Simple Calculator

>>> 1 + 1
2

Import a module

>>> import sys
>>> sys
<module 'sys' (built-in)>

Show platform

>>> sys.platform
'darwin'

Show paths

>>> sys.path
['', '/usr/local/Cellar/python3/3.5.1/Frameworks/Python.framework/Versions/3.5/lib/python35.zip', '/usr/local/Cellar/python3/3.5.1/Frameworks/Python.framework/Versions/3.5/lib/python3.5', '/usr/local/Cellar/python3/3.5.1/Frameworks/Python.framework/Versions/3.5/lib/python3.5/plat-darwin', '/usr/local/Cellar/python3/3.5.1/Frameworks/Python.framework/Versions/3.5/lib/python3.5/lib-dynload', '/usr/local/lib/python3.5/site-packages']
>>> import os
>>> os.getcwd()
/path/to/current/directory

Builtin Module

>>> __builtins__
<module '__builtin__' (built-in)>

Getting Help

Check all available methods and fields(press TAB twice after typing sys.:

>>> sys.<TAB><TAB>
sys.__class__(              sys.__name__
sys._getframe(              sys.exec_prefix
sys.hash_info               sys.setcheckinterval(
sys.__delattr__(            sys.__ne__(
...

Or you can use dir:

>>> dir(sys)
['__displayhook__', '__doc__', '__excepthook__', '__interactivehook__', '__loader__', '__name__', '__package__', '__spec__', '__stderr__', '__stdin__', '__stdout__', '_clear_type_cache', '_current_frames', '_debugmallocstats', '_getframe', '_home', '_mercurial', '_xoptions', 'abiflags', 'api_version', 'argv', 'base_exec_prefix', 'base_prefix', 'builtin_module_names', 'byteorder', 'call_tracing', 'callstats', 'copyright', 'displayhook', 'dont_write_bytecode', 'exc_info', 'excepthook', 'exec_prefix', 'executable', 'exit', 'flags', 'float_info', 'float_repr_style', 'get_coroutine_wrapper', 'getallocatedblocks', 'getcheckinterval', 'getdefaultencoding', 'getdlopenflags', 'getfilesystemencoding', 'getprofile', 'getrecursionlimit', 'getrefcount', 'getsizeof', 'getswitchinterval', 'gettrace', 'hash_info', 'hexversion', 'implementation', 'int_info', 'intern', 'is_finalizing', 'last_traceback', 'last_type', 'last_value', 'maxsize', 'maxunicode', 'meta_path', 'modules', 'path', 'path_hooks', 'path_importer_cache', 'platform', 'prefix', 'ps1', 'ps2', 'set_coroutine_wrapper', 'setcheckinterval', 'setdlopenflags', 'setprofile', 'setrecursionlimit', 'setswitchinterval', 'settrace', 'stderr', 'stdin', 'stdout', 'thread_info', 'version', 'version_info', 'warnoptions']

Show help

>>> help(sys)

Print doc

>>> print(sys.__doc__)

Stop the REPL

Ctrl-c + Ctrl-d