Role of sys
Python's sys module provides an interface to access variables used or maintained by the interpreter, and provides functions to interact with the interpreter and manipulate Python's runtime environment.
>>> import sys
Common Variables
Returns the version number of the Python interpreter; used when a program needs to be run with the specified version number.
>>> import sys >>> 3.8.5 (tags/v3.8.5:580fbb0, Jul 20 2020, 15:57:54) [MSC v.1924 64 bit (AMD64)]
Indicates the maximum int value carried by the operating system
>>> import sys >>> 9223372036854775807
The integer that gives the maximum Unicode code point value, i.e. 1114111 (hex 0x10FFFF).
>>> import sys >>> 1114111
The path environment variable for the current script, if it doesn't have python find the
>>> import sys >>> ['', 'D:\\Python3.8\\', 'D:\\Python3.8\\DLLs', 'D:\\Python3.8\\lib', 'D:\\Python3.8', 'D:\\Python3.8\\lib\\site-packages']
Returns the operating system platform name, useful when writing cross-platform applications
| systems | return value |
|---|---|
| Windows | ‘win32’ |
| Linux | ‘linux’ |
| Mac | ‘darwin’ |
>>> import sys >>> win32
Take the script name of a python script runtime and the parameters as a list and output it. Implement passing parameters from outside the program like program content
import sys print()
E:\Python> python hello python ['', 'hello', 'python']
A string giving the absolute path to the Python interpreter's executable binary. If Python cannot retrieve the true path to its executable, it will be the empty string or None.
>>> import sys >>> 'D:\\Python3.8\\'
Indicator of local byte order - the value is 'big' on big endian (highest significant bit first) operating systems, and 'little' on little endian (lowest significant bit first) operating systems.
>>> import sys >>> 'little'
sys.version_info
A tuple of five components containing version numbers: major, minor, micro, releaselevel, and serial.
>>> import sys >>> sys.version_info sys.version_info(major=3, minor=7, micro=3, releaselevel='final', serial=0)
sys.api_version
The C API version of this interpreter.
>>> import sys >>> sys.api_version 1013
//
Standard inputs, outputs, errors.
>>> import sys >>> <_io.TextIOWrapper name='<stdin>' mode='r' encoding='utf-8'> >>> <_io.TextIOWrapper name='<stdout>' mode='w' encoding='utf-8'> >>> <_io.TextIOWrapper name='<stderr>' mode='w' encoding='utf-8'>
Common methods
()
Exit the program, exit(0) for normal exit
import sys print((0)) print((1))
Returns the module fields imported by the system, key is the module name, value is the module
>>> import sys
>>>
{'sys': <module 'sys' (built-in)>, 'builtins': <module 'builtins' (built-in)>, '_frozen_importlib': <module 'importlib._bootstrap' (frozen)>, '_imp': <module '_imp' (built-in)>, '_warnings': <module '_warnings' (built-in)>, '_frozen_importlib_external': <module 'importlib._bootstrap_external' (frozen)>, '_io': <module 'io' (built-in)>, 'marshal': <module 'marshal' (built-in)>, 'nt': <module 'nt' (built-in)>, '_thread': <module '_thread' (built-in)>, '_weakref': <module '_weakref' (built-in)>, 'winreg': <module 'winreg' (built-in)>, 'time': <module 'time' (built-in)>, 'zipimport': <module 'zipimport' (frozen)>, '_codecs': <module '_codecs' (built-in)>, 'codecs': <module 'codecs' from 'D:\\Python3.8\\lib\\'>, '': <module '' from 'D:\\Python3.8\\lib\\encodings\\'>, 'encodings': <module 'encodings' from 'D:\\Python3.8\\lib\\encodings\\__init__.py'>, 'encodings.utf_8': <module 'encodings.utf_8' from 'D:\\Python3.8\\lib\\encodings\\utf_8.py'>, '_codecs_cn': <module '_codecs_cn' (built-in)>, '_multibytecodec': <module '_multibytecodec' (built-in)>, '': <module '' from 'D:\\Python3.8\\lib\\encodings\\'>, '_signal': <module '_signal' (built-in)>, '__main__': <module '__main__' (built-in)>, 'encodings.latin_1': <module 'encodings.latin_1' from 'D:\\Python3.8\\lib\\encodings\\latin_1.py'>, '_abc': <module '_abc' (built-in)>, 'abc': <module 'abc' from 'D:\\Python3.8\\lib\\'>, 'io': <module 'io' from 'D:\\Python3.8\\lib\\'>, '_stat': <module '_stat' (built-in)>, 'stat': <module 'stat' from 'D:\\Python3.8\\lib\\'>, '_collections_abc': <module '_collections_abc' from 'D:\\Python3.8\\lib\\_collections_abc.py'>, 'genericpath': <module 'genericpath' from 'D:\\Python3.8\\lib\\'>, 'ntpath': <module 'ntpath' from 'D:\\Python3.8\\lib\\'>, '': <module 'ntpath' from 'D:\\Python3.8\\lib\\'>, 'os': <module 'os' from 'D:\\Python3.8\\lib\\'>, '_sitebuiltins': <module '_sitebuiltins' from 'D:\\Python3.8\\lib\\_sitebuiltins.py'>, '_locale': <module '_locale' (built-in)>, '_bootlocale': <module '_bootlocale' from 'D:\\Python3.8\\lib\\_bootlocale.py'>, 'types': <module 'types' from 'D:\\Python3.8\\lib\\'>, 'importlib._bootstrap': <module 'importlib._bootstrap' (frozen)>, 'importlib._bootstrap_external': <module 'importlib._bootstrap_external' (frozen)>, 'warnings': <module 'warnings' from 'D:\\Python3.8\\lib\\'>, 'importlib': <module 'importlib' from 'D:\\Python3.8\\lib\\importlib\\__init__.py'>, '': <module '' from 'D:\\Python3.8\\lib\\importlib\\'>, '': <module '' from 'D:\\Python3.8\\lib\\importlib\\'>, '_operator': <module '_operator' (built-in)>, 'operator': <module 'operator' from 'D:\\Python3.8\\lib\\'>, 'keyword': <module 'keyword' from 'D:\\Python3.8\\lib\\'>, '_heapq': <module '_heapq' (built-in)>, 'heapq': <module 'heapq' from 'D:\\Python3.8\\lib\\'>, 'itertools': <module 'itertools' (built-in)>, 'reprlib': <module 'reprlib' from 'D:\\Python3.8\\lib\\'>, '_collections': <module '_collections' (built-in)>, 'collections': <module 'collections' from 'D:\\Python3.8\\lib\\collections\\__init__.py'>, '_functools': <module '_functools' (built-in)>, 'functools': <module 'functools' from 'D:\\Python3.8\\lib\\'>, 'contextlib': <module 'contextlib' from 'D:\\Python3.8\\lib\\'>, '': <module '' from 'D:\\Python3.8\\lib\\importlib\\'>, 'mpl_toolkits': <module 'mpl_toolkits' (namespace)>, 'site': <module 'site' from 'D:\\Python3.8\\lib\\'>, 'atexit': <module 'atexit' (built-in)>}
()
Returns a list of all imported module names
>>> import sys >>> () dict_keys(['sys', 'builtins', '_frozen_importlib', '_imp', '_warnings', '_frozen_importlib_external', '_io', 'marshal', 'nt', '_thread', '_weakref', 'winreg', 'time', 'zipimport', '_codecs', 'codecs', '', 'encodings', 'encodings.utf_8', '_codecs_cn', '_multibytecodec', '', '_signal', '__main__', 'encodings.latin_1', '_abc', 'abc', 'io', '_stat', 'stat', '_collections_abc', 'genericpath', 'ntpath', '', 'os', '_sitebuiltins', '_locale', '_bootlocale', 'types', 'importlib._bootstrap', 'importlib._bootstrap_external', 'warnings', 'importlib', '', '', '_operator', 'operator', 'keyword', '_heapq', 'heapq', 'itertools', 'reprlib', '_collections', 'collections', '_functools', 'functools', 'contextlib', '', 'mpl_toolkits', 'site', 'atexit'])
()
Returns the name of the current default string encoding used by the Unicode implementation.
>>> import sys >>> () 'utf-8'
()
Returns the encoding name used to convert between Unicode filenames and byte filenames
>>> import sys >>> () utf-8
()
Returns the maximum number of recursions
>>> import sys >>> () # View the maximum recursion depth of the current interpreter 1000
(num)
Setting the maximum number of recursions
>>> import sys >>> (1100) # Set the maximum recursion depth of the interpreter to 1100 >>> () # Check the maximum recursion depth of the current interpreter again 1100
()
Get the size of the memory occupied by the object (expressed in bytes)
>>> import sys >>> for obj in [int(), float(), list(), tuple(), set(), dict(), object]: ... print(str(obj.__class__).ljust(20), (obj)) ... <class 'int'> 24 <class 'float'> 24 <class 'list'> 56 <class 'tuple'> 40 <class 'set'> 216 <class 'dict'> 232 <class 'type'> 416
(obj)
Returns the reference count of obj. The returned count is usually one higher than expected because it contains (temporary) references as arguments.
>>> import sys >>> a = [1,2,3] >>> b = a >>> c = b >>> (a) 4
sys.exc_info()
Get the exception class that is currently being handled, theexc_type、exc_value、exc_tracebackDetails of the currently handled exception
>>> import sys >>> sys.exc_info() (None, None, None)
()
Get the version of Windows, valid on Windows systems
>>> import sys >>> () (major=10, minor=0, build=19041, platform=2, service_pack='')
()
Reading a line from standard input reads the line breaks at the end
()
Write to standard output
>>> import sys
>>> ("hello world")
hello world11
summarize
That's all for this post, I hope it was helpful and I hope you'll check back for more from me!