如何获取python来读取.txt文件的第n行? [英] How can I get python to read every nth line of a .txt file?

问题描述

如果我想让python读取文件的第2行(或第4行)，我如何告诉它这样做?另外，如果我想读取.txt文件的第2行，但之后每4行读取(下一行将是6行，然后是10行，依此类推)，我该如何做呢?

If I wanted python to read every 2nd (or every 4th) line of a file, how could I tell it to do so? Additionally, if I wanted to read line 2 of a .txt file, but every 4 lines after that (next line would be line 6, then 10, and so on forth), how could I make it do so?

推荐答案

您不能... [使用纯I/O函数进行操作]您必须阅读所有行，并使代码仅忽略您所需要的行不需要.

You can't... [do it using pure I/O functions] You have to read all lines and simply make your code ignore the lines that you do not need.

例如:

with open(filename) as f:
    lines = f.readlines()
desired_lines = lines[start:end:step]

在上面的代码中，将开始，结束和步骤替换为所需的值，例如"...如果我想读取.txt文件的第2行，但之后每4行..." 您会这样:

In the code above replace start, end, and step with desired values, e.g., "...if I wanted to read line 2 of a .txt file, but every 4 lines after that..." you would do like this:

desired_lines = lines[1::4]

这篇关于如何获取python来读取.txt文件的第n行?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！