python2.7以下出 NameError: global name 'FileNotFoundError' is not defined的解决方案

原文链接：http://blog.csdn.net/waiwai3/article/details/77461276

处理文件不存在使用FileNotFoundError来处理异常

Python版本：2.6

python代码：

def count_words(filename):         try:                 with open(filename) as f_obj:                         contents = f_obj.read()         except FileNotFoundError:                 msg = "Sorry, the file " + filename + " does not exist."                 print(msg)         else:                 words = contents.split()                 num_words = len(words)                 print("The file " + filename + " has about " + str(num_words) +" words.") filename = 'alice.txt' count_words(filename

运行结果：

Traceback (most recent call last):   File "./count_words.py", line 15, in      count_words(filename)   File "./count_words.py", line 6, in count_words     except FileNotFoundError: NameError: global name 'FileNotFoundError' is not define

报错原因：

FileNotFoundError为python3使用的文本不存在异常处理方法

在python2.7中使用IOError

修改后的python代码

#!/usr/bin/env python def count_words(filename):         try:                 with open(filename) as f_obj:                         contents = f_obj.read()         #except FileNotFoundError:         except IOError:                 msg = "Sorry, the file " + filename + " does not exist."                 print(msg)         else:                 words = contents.split()                 num_words = len(words)                 print("The file " + filename + " has about " + str(num_words) +" words.") filename = 'alice.txt' count_words(filename)

运行结果：

Sorry, the file alice.txt does not exist