如何跳过文本文件中的某一行并继续阅读python中的下一行？

Question

我一直在寻找这个答案,但并没有得到它.

我有一个看起来像这样的文本文件

who are you????
who are you man?
who are you!!!!
who are you? man or woman?

我想跳过它的行man并打印

who are you????
who are you!!!!

我的代码到目前为止

f = open("test.txt", "r")
word = "man"
for line in f:
    if word in line:
        f.next()
    else:
        print line

这仅打印第一行

who are you????

我该如何解决这个问题？

谢谢您的帮助.

Answer 1

没有必要if else在for循环中添加语句，因此您可以通过以下方式修改代码：

f = open("test.txt", "r")
word = "man"
for line in f:
    if not word in line:
        print line

此外，您的代码中的问题是您f.next()直接在用于扫描文件的 for 循环中使用。这是因为当该行包含“man”字时，您的代码会跳过两行。

如果if else因为这只是更复杂问题的一个示例而需要保留语句，则可以使用以下代码：

f = open("test.txt", "r")
word = "man"
for line in f:
    if word in line:
        continue
    else:
        print line

使用continue，您可以跳过一个循环的迭代，从而达到您的目标。

正如 Alex Fung 所建议的那样，使用会更好with，因此您的代码会变成这样：

with open("test.txt", "r") as test_file:
    for line in test_file:
        if "man" not in line:
            print line

Answer 2

问题

使用当前代码,当前行包含"man":

• 你什么都不打印.那是对的.
• 你也跳过下一行.那是你的问题!
• f.next()已经for line in f:在每次迭代时被隐含地称为.所以f.next()当你找到"男人"时你实际上会打两次电话.
• 如果文件的最后一行包含a "man",Python将抛出异常,因为没有下一行.

您可能一直在寻找continue,这也可以达到预期的效果,但是复杂且不必要.请注意,它next在Perl和Ruby中调用,这可能会令人困惑.

例

who are you????            # <- This line gets printed, because there's no "man" in it
who are you man?           # word in line is True. Don't print anything. And skip next line
who are you!!!!            # Line is skipped because of f.next()
who are you? man or woman? # word in line is True. Don't print anything. 
                           #   Try to skip next line, but there's no next line anymore.
                           #   The script raises an exception : StopIteration

正确的代码

别忘了关闭文件.您可以自动执行以下操作with:

word = "man"
with open("test.txt") as f:
    for line in f:
        if not word in line:
            print line, # <- Note the comma to avoid double newlines