我不知道爲什麼它是錯誤的，當我導入ctypes

我改變了內置函數len的定義，然後我試圖導入ctypes模塊。但我不知道爲什麼它會出現錯誤，當我這樣做時。這裏是我的代碼：我不知道爲什麼它是錯誤的，當我導入ctypes

import builtins 

def func(obj): 
    print("Length: %d" % len(obj)) 
builtins.len = lambda obj: "Bad!!!" 

import ctypes

那麼這裏就是錯誤的tracback：

Traceback (most recent call last): 


    File "<stdin>", line 1, in <module> 
    File "<frozen importlib._bootstrap>", line 969, in _find_and_load 
    File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked 
    File "<frozen importlib._bootstrap>", line 673, in _load_unlocked 
    File "<frozen importlib._bootstrap_external>", line 661, in exec_module 
    File "<frozen importlib._bootstrap_external>", line 772, in get_code 
    File "<frozen importlib._bootstrap_external>", line 491, in _code_to_bytecode 
    File "<frozen importlib._bootstrap_external>", line 42, in _w_long 
ValueError: invalid literal for int() with base 10: 'Bad!!!' 
Error in sys.excepthook: 
Traceback (most recent call last): 
    File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 53, in apport_excepthook 
    if not enabled(): 
    File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 24, in enabled 
    import re 
    File "<frozen importlib._bootstrap>", line 969, in _find_and_load 
    File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked 
    File "<frozen importlib._bootstrap>", line 673, in _load_unlocked 
    File "<frozen importlib._bootstrap_external>", line 661, in exec_module 
    File "<frozen importlib._bootstrap_external>", line 772, in get_code 
    File "<frozen importlib._bootstrap_external>", line 491, in _code_to_bytecode 
    File "<frozen importlib._bootstrap_external>", line 42, in _w_long 
ValueError: invalid literal for int() with base 10: 'Bad!!!' 

Original exception was: 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
    File "<frozen importlib._bootstrap>", line 969, in _find_and_load 
    File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked 
    File "<frozen importlib._bootstrap>", line 673, in _load_unlocked 
    File "<frozen importlib._bootstrap_external>", line 661, in exec_module 
    File "<frozen importlib._bootstrap_external>", line 772, in get_code 
    File "<frozen importlibbootstrap_external>", line 491, in _code_to_bytecode 
    File "<frozen importlib._bootstrap_external>", line 42, in _w_long 
ValueError: invalid literal for int() with base 10: 'Bad!!!'

這困擾了我很多。非常感謝如果有人能幫助我！

來源

2017-09-09 duan xingzhe

你爲什麼不解？改變嚴重依賴基本內建的功能，然後嘗試使用它（間接地通過導入），因爲它本來就是*會導致錯誤，不是？ – jedwards

你的意思是，當我試圖導入ctypes時，改變後的len函數被執行了嗎？ @jedwards –

當您嘗試導入ctypes時，更改的len樂趣肯定會被調用（請參見ValueError：對於int（），其基數爲10：'Bad !!!'）。我不知道爲什麼，除非版本的ctypes依賴於未來的包。 – jedwards

因爲你的len函數返回非整數字符串。

你只跑了完全相同的行爲，你可以有：

>>> int("I should know playing with builtins is always a bad thing") 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
ValueError: invalid literal for int() with base 10: 'lol'

嘗試更新喜歡你的代碼：

builtins.len = lambda obj: "123"

看到它。

來源

2017-09-09 10:26:04 Arount

它的工作原理！謝謝！ –

我不知道爲什麼它是錯誤的，當我導入ctypes

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