如何使用Python删除特定单词后的一行

Question

我有一个文本文件（ input.txt ），它包含：

COMPDAT

First line 123 456

Second line 4d5 fdf

COMPDAT

Computer 459

Computer 999

COMPDAT

Mouse qwerty

main 478

现在，我需要删除input.txt文件中每个COMPDAT关键字之后的第一行。
如何使用Python做到这一点？

我尝试使用此脚本，但是，它在每个现有行之间添加了一个空行：

import fileinput    
fin = fileinput.input('input.txt', inplace=1)

for line in fin:    
    print (line),    
    if line.strip() == 'COMPDAT':    
        next(fin, None)

Answer 1

import fileinput    
fin = fileinput.input('input.txt', inplace=True)

for line in fin:    
    print(line,end='')
    if line.strip() == 'COMPDAT':    
        next(fin, None)

Answer 2

首先读取文件，获取所需的所有行，然后将这些行写入同一文件中。

input_file = open("input.txt", 'r')
prev_line = False
lines =[]
for line in input_file:
 if not prev_line:
    lines.append(line)
 prev_line=False
 if "COMPDAT" in line:
    prev_line=True
input_file.close()

input_file = open("input.txt", 'w')
for line in lines:
   input_file.write(line)
input_file.close()

Answer 3

基于@Sanjay的答案，使用生成器的另一种可能性。

def line_and_line_before(file):
    prev_line = None
    for line in file:
        yield (prev_line, line)
        prev_line = line

input_file = open("input.txt", 'r')
lines = []

for prev_line, line in line_and_line_before(input_file):
     if not prev_line or "COMPDAT" not in prev_line:
         lines.append(line)

input_file.close()

input_file = open("input.txt", 'w')
for line in lines:
    input_file.write(line)
input_file.close()