Python Inspect用法及代碼示例

檢查模塊有助於檢查我們編寫的代碼中存在的對象。由於Python是一種OOP語言，所有編寫的代碼本質上都是這些對象之間的交互，因此檢查module 在檢查某些模塊或某些對象時變得非常有用。我們還可以使用它來詳細分析某些函數調用或回溯，以便更輕鬆地進行調試。

檢查模塊提供了很多方法，這些方法可以分為兩類，即驗證token類型的方法和檢索token來源的方法。下麵提到了這兩類最常用的方法。

驗證token類型的方法：

• isclass(): isclass()如果該對象是一個類，則該方法返回 True，否則返回 false。當它與getmembers()函數它顯示了類及其類型。它用於檢查現場課程。

例子：

# import required modules 
import inspect 
  
# create class 
class A(object): 
    pass
  
# use isclass() 
print(inspect.isclass(A)) 

輸出：

True

• ismodule():這返回真的如果給定的參數是導入的模塊。

例子：

# import required modules 
import inspect 
import numpy 
  
# use ismodule() 
print(inspect.ismodule(numpy))

輸出：

True

• isfunction():該方法返回真的如果給定的參數是內置函數名稱。

例子：

# import required modules 
import inspect 
  
# explicit function 
def fun(a): 
    return 2*a 
  
# use isfunction() 
print(inspect.isfunction(fun))

輸出：

True

• ismethod():該方法用於檢查傳遞的參數是否是方法的名稱。

例子：

# import required modules 
import inspect 
import collections 
  
# use ismethod() 
print(inspect.ismethod(collections.Counter)) 

輸出：

False

獲取token來源的方法：

• getclasstree()： 這getclasstree()方法將有助於獲取和檢查類層次結構。它返回該類及其前麵的基類的元組。與 getmro() 返回基類的方法有助於理解類層次結構。

示例 1：

# import required module 
import inspect 
  
# create classes 
class A(object): 
    pass
  
class B(A): 
    pass
  
class C(B): 
    pass
  
# not nested 
print(inspect.getmro(C))   

輸出：

(<class ‘__main__.C’>, <class ‘__main__.B’>, <class ‘__main__.A’>, <class ‘object’>)

示例 2：

# import required module 
import inspect 
  
# create classes 
class A(object): 
    pass
  
class B(A): 
    pass
  
class C(B): 
    pass
  
# nested list of tuples 
for i in (inspect.getclasstree(inspect.getmro(C))): 
    print(i) 

輸出：

(<class ‘object’>, ()) [(<class ‘__main__.A’>, (<class ‘object’>,)), [(<class ‘__main__.B’>, (<class ‘__main__.A’>,)), [(<class ‘__main__.C’>, (<class ‘__main__.B’>,))]]]

• getmembers():此方法返回作為此方法的參數傳遞的模塊中存在的成員函數。

例子：

# import required module 
import inspect 
import math 
  
# shows the member functions 
# of any module or object 
print(inspect.getmembers(math)) 

輸出：

[(‘__doc__’, ‘This module provides access to the mathematical functions\ndefined by the C standard.’), (‘__loader__’, <class ‘_frozen_importlib.BuiltinImporter’>), (‘__name__’, ‘math’), (‘__package__’, ”), (‘__spec__’, ModuleSpec(name=’math’, loader=<class ‘_frozen_importlib.BuiltinImporter’>, origin=’built-in’)), (‘acos’, <built-in function acos>), (‘acosh’, <built-in function acosh>), (‘asin’, <built-in function asin>), (‘asinh’, <built-in function asinh>), (‘atan’, <built-in function atan>), (‘atan2’, <built-in function atan2>), (‘atanh’, <built-in function atanh>), (‘ceil’, <built-in function ceil>), (‘copysign’, <built-in function copysign>), (‘cos’, <built-in function cos>), (‘cosh’, <built-in function cosh>), (‘degrees’, <built-in function degrees>), (‘e’, 2.718281828459045), (‘erf’, <built-in function erf>), (‘erfc’, <built-in function erfc>), (‘exp’, <built-in function exp>), (‘expm1’, <built-in function expm1>), (‘fabs’, <built-in function fabs>), (‘factorial’, <built-in function factorial>), (‘floor’, <built-in function floor>), (‘fmod’, <built-in function fmod>), (‘frexp’, <built-in function frexp>), (‘fsum’, <built-in function fsum>), (‘gamma’, <built-in function gamma>), (‘gcd’, <built-in function gcd>), (‘hypot’, <built-in function hypot>), (‘inf’, inf), (‘isclose’, <built-in function isclose>), (‘isfinite’, <built-in function isfinite>), (‘isinf’, <built-in function isinf>), (‘isnan’, <built-in function isnan>), (‘ldexp’, <built-in function ldexp>), (‘lgamma’, <built-in function lgamma>), (‘log’, <built-in function log>), (‘log10’, <built-in function log10>), (‘log1p’, <built-in function log1p>), (‘log2’, <built-in function log2>), (‘modf’, <built-in function modf>), (‘nan’, nan), (‘pi’, 3.141592653589793), (‘pow’, <built-in function pow>), (‘radians’, <built-in function radians>), (‘remainder’, <built-in function remainder>), (‘sin’, <built-in function sin>), (‘sinh’, <built-in function sinh>), (‘sqrt’, <built-in function sqrt>), (‘tan’, <built-in function tan>), (‘tanh’, <built-in function tanh>), (‘tau’, 6.283185307179586), (‘trunc’, <built-in function trunc>)]

• signature(): signature()方法幫助用戶理解要傳遞給函數的屬性。

# import required modules 
import inspect 
import collections 
  
# use signature() 
print(inspect.signature(collections.Counter)) 

輸出：

(*args, **kwds)

• stack():此方法有助於檢查解釋器堆棧或調用函數的順序。

# import required module 
import inspect 
  
# define explicit function 
def Fibonacci(n): 
    if n < 0: 
        return 0
  
    elif n == 0: 
        return 0
  
    elif n == 1: 
        return 1
    else: 
        return Fibonacci(n-1)+Fibonacci(n-2) 
  
  
# Driver Program 
(Fibonacci(12)) 
  
# inpsecting interpreter stack 
print(inspect.stack()) 

輸出：

[FrameInfo(frame=<frame at 0x000002AC9BF9FD18, file ‘<ipython-input-8-3080f52ca090>’, line 22, code <module>>, filename='<ipython-input-8-3080f52ca090>’, lineno=22, function='<module>’, code_context=[‘print(inspect.stack())\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BAABA38, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\interactiveshell.py’, line 3331, code run_code>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\interactiveshell.py’, lineno=3331, function=’run_code’, code_context=[‘                    exec(code_obj, self.user_global_ns, self.user_ns)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9A94B608, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\interactiveshell.py’, line 3254, code run_ast_nodes>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\interactiveshell.py’, lineno=3254, function=’run_ast_nodes’, code_context=[‘                    if (await self.run_code(code, result,  async_=asy)):\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BA8D768, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\interactiveshell.py’, line 3063, code run_cell_async>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\interactiveshell.py’, lineno=3063, function=’run_cell_async’, code_context=[‘                       interactivity=interactivity, compiler=compiler, result=result)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9C452618, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\async_helpers.py’, line 68, code _pseudo_sync_runner>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\async_helpers.py’, lineno=68, function=’_pseudo_sync_runner’, code_context=[‘        coro.send(None)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BEE1778, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\interactiveshell.py’, line 2886, code _run_cell>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\interactiveshell.py’, lineno=2886, function=’_run_cell’, code_context=[‘            return runner(coro)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BE85FC8, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\interactiveshell.py’, line 2858, code run_cell>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\IPython\\core\\interactiveshell.py’, lineno=2858, function=’run_cell’, code_context=[‘                raw_cell, store_history, silent, shell_futures)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9C464208, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\zmqshell.py’, line 536, code run_cell>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\zmqshell.py’, lineno=536, function=’run_cell’, code_context=[‘        return super(ZMQInteractiveShell, self).run_cell(*args, **kwargs)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BECB108, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\ipkernel.py’, line 300, code do_execute>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\ipkernel.py’, lineno=300, function=’do_execute’, code_context=[‘                res = shell.run_cell(code, store_history=store_history, silent=silent)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BF9FAF8, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\gen.py’, line 209, code wrapper>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\gen.py’, lineno=209, function=’wrapper’, code_context=[‘                    yielded = next(result)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BECAEB8, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\kernelbase.py’, line 541, code execute_request>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\kernelbase.py’, lineno=541, function=’execute_request’, code_context=[‘                user_expressions, allow_stdin,\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BF9F6B8, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\gen.py’, line 209, code wrapper>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\gen.py’, lineno=209, function=’wrapper’, code_context=[‘                    yielded = next(result)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BEE1BD8, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\kernelbase.py’, line 268, code dispatch_shell>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\kernelbase.py’, lineno=268, function=’dispatch_shell’, code_context=[‘                yield gen.maybe_future(handler(stream, idents, msg))\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BFA0378, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\gen.py’, line 209, code wrapper>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\gen.py’, lineno=209, function=’wrapper’, code_context=[‘                    yielded = next(result)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9C44A848, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\kernelbase.py’, line 361, code process_one>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\kernelbase.py’, lineno=361, function=’process_one’, code_context=[‘        yield gen.maybe_future(dispatch(*args))\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BE85368, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\gen.py’, line 748, code run>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\gen.py’, lineno=748, function=’run’, code_context=[‘                        yielded = self.gen.send(value)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9C456048, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\gen.py’, line 787, code inner>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\gen.py’, lineno=787, function=’inner’, code_context=[‘                self.run()\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BE882D8, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\ioloop.py’, line 743, code _run_callback>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\ioloop.py’, lineno=743, function=’_run_callback’, code_context=[‘            ret = callback()\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9C4519A8, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\ioloop.py’, line 690, code <lambda>>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\ioloop.py’, lineno=690, function='<lambda>’, code_context=[‘                lambda f: self._run_callback(functools.partial(callback, future))\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BEE5808, file ‘D:\\Software\\Anaconda\\lib\\asyncio\\events.py’, line 88, code _run>, filename=’D:\\Software\\Anaconda\\lib\\asyncio\\events.py’, lineno=88, function=’_run’, code_context=[‘            self._context.run(self._callback, *self._args)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9BEC9798, file ‘D:\\Software\\Anaconda\\lib\\asyncio\\base_events.py’, line 1782, code _run_once>, filename=’D:\\Software\\Anaconda\\lib\\asyncio\\base_events.py’, lineno=1782, function=’_run_once’, code_context=[‘                handle._run()\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9C44BB88, file ‘D:\\Software\\Anaconda\\lib\\asyncio\\base_events.py’, line 538, code run_forever>, filename=’D:\\Software\\Anaconda\\lib\\asyncio\\base_events.py’, lineno=538, function=’run_forever’, code_context=[‘                self._run_once()\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9C44B9A8, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\platform\\asyncio.py’, line 153, code start>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\tornado\\platform\\asyncio.py’, lineno=153, function=’start’, code_context=[‘            self.asyncio_loop.run_forever()\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9C335248, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\kernelapp.py’, line 583, code start>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel\\kernelapp.py’, lineno=583, function=’start’, code_context=[‘            self.io_loop.start()\n’], index=0), FrameInfo(frame=<frame at 0x000002AC9A980F38, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\traitlets\\config\\application.py’, line 664, code launch_instance>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\traitlets\\config\\application.py’, lineno=664, function=’launch_instance’, code_context=[‘        app.start()\n’], index=0), FrameInfo(frame=<frame at 0x000002AC98403228, file ‘D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel_launcher.py’, line 16, code <module>>, filename=’D:\\Software\\Anaconda\\lib\\site-packages\\ipykernel_launcher.py’, lineno=16, function='<module>’, code_context=[‘    app.launch_new_instance()\n’], index=0), FrameInfo(frame=<frame at 0x000002AC985AE468, file ‘D:\\Software\\Anaconda\\lib\\runpy.py’, line 85, code _run_code>, filename=’D:\\Software\\Anaconda\\lib\\runpy.py’, lineno=85, function=’_run_code’, code_context=[‘    exec(code, run_globals)\n’], index=0), FrameInfo(frame=<frame at 0x000002AC97CE5038, file ‘D:\\Software\\Anaconda\\lib\\runpy.py’, line 193, code _run_module_as_main>, filename=’D:\\Software\\Anaconda\\lib\\runpy.py’, lineno=193, function=’_run_module_as_main’, code_context=[‘                     “__main__”, mod_spec)\n’], index=0)]

• getsource():此方法返回模塊、類、方法或函數的源代碼作為參數傳遞getsource()方法。

例子：

# import required modules 
import inspect 
  
def fun(a,b): 
    # product of  
    # two numbers 
    return a*b 
  
# use getsource() 
print(inspect.getsource(fun))

輸出：

def fun(a,b):
    # product of 
    # two numbers
    return a*b

• getmodule():這種方法 返回特定對象的模塊名稱作為此方法中的參數傳遞。

# import required modules 
import inspect 
import collections 
  
# use getmodule() 
print(inspect.getmodule(collections)) 

輸出：

<module ‘collections’ from ‘D:\\Software\\Anaconda\\lib\\collections\\__init__.py’>

• getdoc(): getdoc() 方法 以字符串形式返回此方法中參數的文檔。

例子：

# import required modules 
import inspect 
from tkinter import *
  
# create object 
root = Tk() 
  
# use getdoc() 
print(inspect.getdoc(root)) 

輸出：

Toplevel widget of Tk which represents mostly the main window
of an application. It has an associated Tcl interpreter.