Question

我需要从下面的文本文件中提取值：

fdsjhgjhg
fdshkjhk
Start
Good Morning
Hello World
End
dashjkhjk
dsfjkhk

我需要提取的值是从开始到结束。

with open('path/to/input') as infile, open('path/to/output', 'w') as outfile:
    copy = False
    for line in infile:
        if line.strip() == "Start":
            copy = True
        elif line.strip() == "End":
            copy = False
        elif copy:
            outfile.write(line)

我正在使用的上述代码来自这个问题： Extract Values between two strings in a text file using python

此代码不会包含字符串“Start”和“End”。你会如何包括外围字符串？

Answer 1

@en_Knight几乎是正确的。这是一个解决方案，以满足OP的请求，即分隔符包含在输出中：

with open('path/to/input') as infile, open('path/to/output', 'w') as outfile:
    copy = False
    for line in infile:
        if line.strip() == "Start":
            copy = True
        if copy:
            outfile.write(line)
        # move this AFTER the "if copy"
        if line.strip() == "End":
            copy = False

或者只是在适用的情况下包含write（）：

with open('path/to/input') as infile, open('path/to/output', 'w') as outfile:
    copy = False
    for line in infile:
        if line.strip() == "Start":
            outfile.write(line) # add this
            copy = True
        elif line.strip() == "End":
            outfile.write(line) # add this
            copy = False
        elif copy:
            outfile.write(line)

更新：回答评论中的问题＆＃34;仅使用＆＃39;结束＆＃39;在＆＃39;开始＆＃39;＆＃34;之后，将最后elif line.strip() == "End"更改为：

        elif line.strip() == "End" and copy:
            outfile.write(line) # add this
            copy = False

如果只有一个＆＃34;开始＆＃34;但多个＆＃34;结束＆＃34;线......这听起来很奇怪，但这就是提问者所要求的。

Answer 2

“elif”means“仅在其他案例失败时执行此操作”。它在语法上等同于“else if”，if you're coming from a differnet C-like语言。没有它，堕落应该包括“开始”和“结束”

with open('path/to/input') as infile, open('path/to/output', 'w') as outfile:
    copy = False
    for line in infile:
        if line.strip() == "Start":
            copy = True
        if copy: # flipped to include end, as Dan H pointed out
            outfile.write(line)
        if line.strip() == "End":
            copy = False

Answer 3

RegExp方法：

import re

with open('input.txt') as f:
    data = f.read()

match = re.search(r'\n(Start\n.*?\nEnd)\n', data, re.M | re.S)
if match:
    with open('output.txt', 'w') as f:
        f.write(match.group(1))

复制文件python中的文本部分

3 个答案: