複製部分

Question

我需要從下面的文本文件中提取值：

fdsjhgjhg 
fdshkjhk 
Start 
Good Morning 
Hello World 
End 
dashjkhjk 
dsfjkhk 

我需要提取的值是從開始到結束。

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) 

上面我使用的代碼是從這樣一個問題： Extract Values between two strings in a text file using python

該代碼將不包含字符串「開始」和「結束」只是裏面是什麼他們。你會如何包含周邊字符串？

Answer 1

@en_Knight幾乎是正確的。這裏有一個修復，以滿足業務方案的要求，即分隔符包含在輸出：

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 

或者乾脆包括寫（），它適用於情況：

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：到回答在評論這個問題：「只能用‘結束’一號次數後‘開始’」，最後elif line.strip() == "End"更改爲：

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

這如果只有一個「開始」，但多個「結束」......這聽起來很奇怪，但這是提問者所問的。

Answer 2

「elif」means「只有在其他情況失敗時才這樣做」。它在語法上等同於「else if」，if you're coming from a differnet C-like語言。沒有它，秋季應該照顧包括「開始」和「結束」

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

正則表達式的方法：

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))