python - 使用 Python 从一个文本文件复制到另一个文本文件

Question

我想将某些文本行从一个文本文件复制到另一个文本文件。在我当前的脚本中，当我搜索一个字符串时，它会复制所有内容，我怎样才能只复制文本的某个部分？例如。仅在其中包含“tests/file/myword”时复制行？

当前代码:

#!/usr/bin/env python
f = open('list1.txt')
f1 = open('output.txt', 'a')

doIHaveToCopyTheLine=False

for line in f.readlines():

    if 'tests/file/myword' in line:
        doIHaveToCopyTheLine=True

    if doIHaveToCopyTheLine:
        f1.write(line)

f1.close()
f.close()

Answer 1

单线:

open("out1.txt", "w").writelines([l for l in open("in.txt").readlines() if "tests/file/myword" in l])

推荐使用 with:

with open("in.txt") as f:
    lines = f.readlines()
    lines = [l for l in lines if "ROW" in l]
    with open("out.txt", "w") as f1:
        f1.writelines(lines)

使用更少的内存:

with open("in.txt") as f:
    with open("out.txt", "w") as f1:
        for line in f:
            if "ROW" in line:
                f1.write(line)