在Python中的.txt文件中打印特定行? [英] Print specific line in a .txt file in Python?

问题描述

我有一个.txt文件，其中包含很多行.我想让我的程序问我要打印哪一行，然后将其打印到python shell中. .txt文件称为packages.txt.

I have got a .txt file that contains a lot of lines. I would like my program to ask me what line I would like to print and then print it into the python shell. The .txt file is called packages.txt.

推荐答案

如果您不想预先读取整个文件，则可以简单地进行迭代，直到找到行号为止:

If you don't want to read in the entire file upfront, you could simply iterate until you find the line number:

with open('packages.txt') as f:
    for i, line in enumerate(f, 1):
        if i == num:
            break
print line

或者您也可以使用itertools.islice()切出所需的行(这有点hacky)

Or you could use itertools.islice() to slice out the desired line (this is slightly hacky)

with open('packages.txt') as f:
    for line in itertools.islice(f, num+1, num+2):
        print line

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