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python標準庫中inspect模塊的簡單說明

更新時間：2023年08月02日 11:06:10 作者：阿常囈語

這篇文章主要介紹了python標準庫中inspect模塊的簡單介紹,inspect模塊提供了幾個有用的函數(shù)來幫助獲取有關(guān)活動對象的信息，例如模塊，類，方法，函數(shù)，回溯，框架對象和代碼對象,需要的朋友可以參考下

inspect 模塊作用

(1).對是否是模塊，框架，函數(shù)等進行類型檢查。

(2).獲取源碼

(3).獲取類或函數(shù)的參數(shù)的信息

以下是官方文檔說明:

inspect模塊提供了幾個有用的函數(shù)來幫助獲取有關(guān)活動對象的信息，例如模塊，類，方法，函數(shù)，回溯，框架對象和代碼對象。

例如，它可以幫助您檢查類的內(nèi)容，檢索方法的源代碼，提取和格式化函數(shù)的參數(shù)列表，或獲取顯示詳細回溯所需的所有信息。

inspect

可以比較輕松獲取函數(shù)的參數(shù), 通過 signature(foo).bind(xxx,xxx) 就可以了.

#!/usr/bin/env python3
# -*- coding: UTF-8 -*-
import inspect
def foo(a, b='ham', *args):
    pass
def test(a, *, b):
    print(a,b)
if __name__ == '__main__':
    ba = inspect.signature(foo).bind(a='spam', b='frank')
    ba.apply_defaults()
    print(ba.arguments)  # ordereddict
# OrderedDict([('a', 'spam'), ('b', 'frank'), ('args', ())])

import  inspect 
def foo(a,b,c,*args,**kw):pass
# 拿到函數(shù) 簽名 
sig  = inspect.signature(foo)
str(sig)
'(a, b, c, *args, **kw)'
## 綁定部分參數(shù),  返回一個 BoundArguments 對象 
sig.bind_partial('frank','165cm')
<BoundArguments (a='frank', b='165cm')>
ba =sig.bind_partial('frank','165cm')
## 對于丟失的參數(shù),可以設(shè)置默認值
ba.apply_defaults()
ba.arguments
OrderedDict([('a', 'frank'), ('b', '165cm'), ('args', ()), ('kw', {})])
## signature  還有一個方法  bind
import  inspect 
def foo(a,b,c,*args,**kw):pass
sig =  inspect.signature(foo)
ba = sig.bind('frank','165cm','hello')
ba
<BoundArguments (a='frank', b='165cm', c='hello')>
ba.arguments
OrderedDict([('a', 'frank'), ('b', '165cm'), ('c', 'hello')])
# 指定默認值 
ba.apply_defaults()
ba.arguments
OrderedDict([('a', 'frank'), ('b', '165cm'), ('c', 'hello'), ('args', ()), ('kw', {})])

bind 和 bind_partial 區(qū)別

綁定參數(shù)的,如果用 bind 需要要所有的位置參數(shù) 都要綁定. bind_partial 可以部分進行綁定.

import  inspect 
def foo(a,b,c,*args,**kw):pass
sig =  inspect.signature(foo)
sig
<Signature (a, b, c, *args, **kw)>
sig
<Signature (a, b, c, *args, **kw)>
sig.bind('frank','165cm')
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/usr/local/Cellar/python3/3.6.4_2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/inspect.py", line 2968, in bind
    return args[0]._bind(args[1:], kwargs)
  File "/usr/local/Cellar/python3/3.6.4_2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/inspect.py", line 2883, in _bind
    raise TypeError(msg) from None
TypeError: missing a required argument: 'c'
不支持 部分綁定參數(shù), 所以會報錯, 可以使用 sig.bind_partial
sig.bind_partial('frank','165cm')
<BoundArguments (a='frank', b='165cm')>

The args and kwargs properties can be used to invoke functions:

signature.bind() 返回一個 Boundarguments 對象. 可以通過 args , kwargs 拿到函數(shù)的所有參數(shù).

#!/usr/bin/env python3
# -*- coding: UTF-8 -*-
import inspect
def test(a, *, b):
    print(a, b)
if __name__ == "__main__":
    sig = inspect.signature(test)
    ba = sig.bind(10, b=20)
    test(*ba.args, **ba.kwargs)  # 10 20
# The args and kwargs properties can be used to invoke functions

實用方法

用來判斷函數(shù),類,實例方法, 內(nèi)建方法, function or method等…

def ismodule(object):
def isclass(object):
def ismethod(object):
def ismethoddescriptor(object):
def isfunction(object):
def isbuiltin(object):
def isabstract(object):
def ismethoddescriptor(object):
def isroutine(object):
    """Return true if the object is any kind of function or method."""

舉個例子

#!/usr/bin/env python3
# -*- coding: UTF-8 -*-
"""
@author: Frank 
@contact: frank.chang@shoufuyou.com
@file: test_inspect.py
@time: 2018/5/14 下午1:24
"""
from inspect import getmembers, ismethod, isclass, isfunction
def foo(): pass
class Cat(object):
    def __init__(self, name='kitty'):
        self.name = name
    def sayHi(self):
        print(self.name + '  says Hi!')
    def fun1(self):
        print('fun1 is running')
if __name__ == '__main__':
    cat = Cat('frank')
    cat.sayHi()
    print(isclass(cat))  # False
    print(isclass(Cat))  # True
    print(ismethod(cat.sayHi))  # True
    print(isfunction(cat.sayHi))  # False
    print(isfunction(foo))  # true
    print(ismethod(cat.fun1))  # True

getmemory

if __name__ == '__main__':
    cat = Cat('frank')
    # print(getmembers(cat))
    for member in getmembers(cat):
        print(member)

# 結(jié)果如下
# ('__class__', <class '__main__.Cat'>)
# ('__delattr__', <method-wrapper '__delattr__' of Cat object at 0x10b213dd8>)
# ('__dict__', {'name': 'frank'})
# ('__dir__', <built-in method __dir__ of Cat object at 0x10b213dd8>)
# ('__doc__', None)
# ('__eq__', <method-wrapper '__eq__' of Cat object at 0x10b213dd8>)
# ('__format__', <built-in method __format__ of Cat object at 0x10b213dd8>)
# ('__ge__', <method-wrapper '__ge__' of Cat object at 0x10b213dd8>)
# ('__getattribute__', <method-wrapper '__getattribute__' of Cat object at 0x10b213dd8>)
# ('__gt__', <method-wrapper '__gt__' of Cat object at 0x10b213dd8>)
# ('__hash__', <method-wrapper '__hash__' of Cat object at 0x10b213dd8>)
# ('__init__', <bound method Cat.__init__ of <__main__.Cat object at 0x10b213dd8>>)
# ('__init_subclass__', <built-in method __init_subclass__ of type object at 0x7fc8afc24358>)
# ('__le__', <method-wrapper '__le__' of Cat object at 0x10b213dd8>)
# ('__lt__', <method-wrapper '__lt__' of Cat object at 0x10b213dd8>)
# ('__module__', '__main__')
# ('__ne__', <method-wrapper '__ne__' of Cat object at 0x10b213dd8>)
# ('__new__', <built-in method __new__ of type object at 0x10afc86c0>)
# ('__reduce__', <built-in method __reduce__ of Cat object at 0x10b213dd8>)
# ('__reduce_ex__', <built-in method __reduce_ex__ of Cat object at 0x10b213dd8>)
# ('__repr__', <method-wrapper '__repr__' of Cat object at 0x10b213dd8>)
# ('__setattr__', <method-wrapper '__setattr__' of Cat object at 0x10b213dd8>)
# ('__sizeof__', <built-in method __sizeof__ of Cat object at 0x10b213dd8>)
# ('__str__', <method-wrapper '__str__' of Cat object at 0x10b213dd8>)
# ('__subclasshook__', <built-in method __subclasshook__ of type object at 0x7fc8afc24358>)
# ('__weakref__', None)
# ('fun1', <bound method Cat.fun1 of <__main__.Cat object at 0x10b213dd8>>)
# ('name', 'frank')
# ('sayHi', <bound method Cat.sayHi of <__main__.Cat object at 0x10b213dd8>>)