如果 findall 找到搜索模式，则在文件中插入新行答案

【问题标题】：insert a new line to a file if findall finds a search pattern如果 findall 找到搜索模式，则在文件中插入新行
【发布时间】：2018-12-10 07:56:21
【问题描述】：

我想在findall 找到搜索模式后向文件添加新行。我使用的代码只将输入文件的内容写入输出文件。它不会在输出文件中添加新行。如何修复我的代码？

import re
text = """
Hi! How are you?
Can you hear me?
"""
with open("input.txt", "r") as infile:
    readcontent = infile.readlines()

with open("output.txt", "w") as out_file:
    for line in readcontent:
    x1 = re.findall(text, line)
    if line == x1:
        line = line + text
    out_file.write(line)

输入.txt：

ricochet robots
settlers of catan
acquire
Hi! How are you?
Can you hear me?
this is very valuable
finish

所需的输出.txt：

ricochet robots
settlers of catan
acquire
Hi! How are you?
Can you hear me?

Added new line

this is very valuable
finish

【问题讨论】：

基本上，您需要在每个“你能听到我的声音吗？”之后换行。 ?
只有一行“你能听到我说话吗？”在输入文件中。所以在那之后我只需要一个新行。
一行或多行，regex 在这里似乎有点矫枉过正。
@klutt 实际输出类似于所需的输出。正如我之前所说，我需要使用findall 在输入文件中查找多行。实际输入更复杂。

标签： python regex python-3.x python-2.7 findall

【解决方案1】：

这里不要使用regex。检查当前行，如果是要检查的行，则添加一个换行符。

with open("output.txt", "w") as out_file:
    for line in readcontent:
        out_file.write(line)
        if line.strip() == 'Can you hear me?':
            out_file.write('\n')

如果您需要 regex 本身，请选择以下内容（尽管我绝不会推荐）：

with open("output.txt", "w") as out_file:
    for line in readcontent:
        out_file.write(line)
        if re.match('Can you hear me?', line.strip()):
            out_file.write('\n')

【讨论】：

请注意，我需要使用findall。
@erhan 这里不适合使用findall。

【解决方案2】：

尝试遍历每一行并检查您的文本是否存在。

例如：

res = []
with open(filename, "r") as infile:
    for line in infile:
        if line.strip() == "Hi! How are you?":
            res.append(line.strip())
            lineVal = (next(infile)).strip() 
            if lineVal == "Can you hear me?":
                res.append(lineVal)
                res.append("\n Added new line \n")
        else:
            res.append(line.strip())



with open(filename1, "w") as out_file:
    for line in res:
        out_file.write(line+"\n")

输出：

ricochet robots
settlers of catan
acquire
Hi! How are you?
Can you hear me?

 Added new line 

this is very valuable
finish

【讨论】：

我需要使用 findall 但你的代码没有使用它。
这是一个没有正则表达式的解决方案。

【解决方案3】：

这是你想要的吗：

text = "Can you hear me?"
with open("input.txt", "r") as infile:
    readcontent = infile.readlines()

with open("output.txt", "w") as out_file:
    for idx,line in enumerate(readcontent):
       if line.rstrip() == text:
           line+='\nAdded new line\n\n'
       out_file.write(line)

output.txt 看起来像：

ricochet robots
settlers of catan
acquire
Hi! How are you?
Can you hear me?

Added new line

this is very valuable
finish

【讨论】：