使用python在文本文件中提取两个字符串之间的值

Question

假设我有一个包含以下内容的文本文件

fdsjhgjhg
fdshkjhk
Start
Good Morning
Hello World
End
dashjkhjk
dsfjkhk

现在我需要编写一个Python代码,它将读取文本文件并将内容复制到Start和end之间另一个文件.

我写了以下代码.

inFile = open("data.txt")
outFile = open("result.txt", "w")
buffer = []
keepCurrentSet = True
for line in inFile:
    buffer.append(line)
    if line.startswith("Start"):
        #---- starts a new data set
        if keepCurrentSet:
            outFile.write("".join(buffer))
        #now reset our state
        keepCurrentSet = False
        buffer = []
    elif line.startswith("End"):
        keepCurrentSet = True
inFile.close()
outFile.close()

我没有按预期获得所需的输出我刚刚开始我想要得到的是开始和结束之间的所有线路.不包括开始和结束.

Answer 1

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
            continue
        elif line.strip() == "End":
            copy = False
            continue
        elif copy:
            outfile.write(line)

Answer 2

如果文本文件不一定很大，则可以获取文件的全部内容，然后使用正则表达式：

import re
with open('data.txt') as myfile:
    content = myfile.read()

text = re.search(r'Start\n.*?End', content, re.DOTALL).group()
with open("result.txt", "w") as myfile2:
    myfile2.write(text)

Answer 3

我不是 Python 专家，但是这段代码应该可以完成这项工作。

inFile = open("data.txt")
outFile = open("result.txt", "w")
keepCurrentSet = False
for line in inFile:
    if line.startswith("End"):
        keepCurrentSet = False

    if keepCurrentSet:
        outFile.write(line)

    if line.startswith("Start"):
        keepCurrentSet = True
inFile.close()
outFile.close()

Answer 4

使用itertools.dropwhile，itertools.takewhile，itertools.islice：

import itertools

with open('data.txt') as f, open('result.txt', 'w') as fout:
    it = itertools.dropwhile(lambda line: line.strip() != 'Start', f)
    it = itertools.islice(it, 1, None)
    it = itertools.takewhile(lambda line: line.strip() != 'End', it)
    fout.writelines(it)

更新：正如inspectorG4dget所说，以上代码在第一个块上进行了复制。要复制多个块，请使用以下命令：

import itertools

with open('data.txt', 'r') as f, open('result.txt', 'w') as fout:
    while True:
        it = itertools.dropwhile(lambda line: line.strip() != 'Start', f)
        if next(it, None) is None: break
        fout.writelines(itertools.takewhile(lambda line: line.strip() != 'End', it))