Answer 1

Answer 2

Answer 3

后人的完整示例：

from itertools import izip, izip_longest

file1name = '/some/path/and/file'
file2name = '/another/path/and/another/file'

with open(file1name) as file1, open(file2name) as file2:
    for line1, line2 in izip(file1, file2):   # or izip_longest
        # do something with the lines

使用with可确保在使用后清除文件，即使发生异常也是如此。