python - 使用 python 从文本文件中读取 - 第一行被遗漏

Question

我有一个名为 test 的文件，其中包含以下内容:

a
b
c
d
e
f
g

我正在使用以下 python 代码逐行读取此文件并将其打印出来:

with open('test.txt') as x:
    for line in x:
        print(x.read())

这样做的结果是打印出文本文件除第一行以外的内容，即结果是:

b
c
d
e
f
g 

有谁知道为什么它可能会丢失文件的第一行？

Answer 1

因为 for line in x 遍历每一行。

with open('test.txt') as x:
    for line in x:
        # By this point, line is set to the first line
        # the file cursor has advanced just past the first line
        print(x.read())
        # the above prints everything after the first line
        # file cursor reaches EOF, no more lines to iterate in for loop

也许你的意思是:

with open('test.txt') as x:
    print(x.read())

一次性全部打印，或者:

with open('test.txt') as x:
    for line in x:
        print line.rstrip()

逐行打印。建议使用后者，因为您不需要一次将文件的全部内容加载到内存中。