复制文件python中的文本部分

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头到尾。

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)

我使用的上面的代码来自这个问题： Extract Values between two strings in a text file using python

此代码将不包括字符串“开始”和“结束”，只是其中的内容。您将如何包含外围字符串？

Answer 1

“elif”means“只有在其他情况失败时才这样做”。它在语法上等同于“else if”、if you're coming from a differnet C-like 语言。没有它，跌倒应该注意包括“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 2

@en_Knight 几乎是对的。这是满足 OP 要求的修复程序，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

或者在它适用的情况下简单地包含 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：要回答评论中的问题“仅在 'Start' 之后使用第一次出现的 'End'”，请将最后一个 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“开始”行但有多个“结束”行，则此方法有效......这听起来很奇怪，但这就是提问者所问的。

Answer 3

正则表达式方法：

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))