Python 替换文本值正则表达式

Question

是否可以仅替换文件中特定文本的值 python？下面的代码替换了字符串，但是我找不到只替换 project_id 或 project_name 的值的方法。

import re 

def replace():
    with open("/Users/test/file.txt", "r") as sources:
        lines = sources.readlines()
    with open("/Users/test/file.txt", "w") as sources:
        for line in lines:
            sources.write(re.sub(r"Settings", 'Project_settings', line))

    
replace()

file.txt

Settings
######################
project_id = "468324678997"
project_name = "test"

输出：

Project_settings
######################
project_id = "468324678997"
project_name = "test"

我想将 project_name 的值替换为“abc”

期望的输出： file.txt

Settings
######################
project_id = "468324678997"
project_name = "abc"

Answer 1

我建议使用配置覆盖字典，而不是正则表达式

这样，您就不会意外地替换所有匹配的文本

def replace(file, overrides):
    with open(file, "r") as sources:
        lines = sources.readlines()
    with open(file, "w") as sources:
        # skip the header rows
        next(lines)
        next(lines)
        for line in lines:
            config_key = line.split(' = ')[0]
            if config_key in overrides:
                sources.write('{} = {}\n'.format(config_key, overrides[config_key]))

overrides = {
  'project_name': 'abc'
}
replace("/Users/test/file.txt", overrides)

可能有更好的 Python 库可以读取属性文件并允许您覆盖特定值

Answer 2

自动化 text-editor 的 regex-replace

我用 任意格式 text-file.

替换每个匹配行的秘诀

作为 re.sub 的参数你可以使用一对 regular-expressions：pattern-to-match 和 replacement，比如 regex-tuple (r'^Settings', r'Project_settings').

存储这些的数据结构可以是元组（对）列表，例如replacements。

import re

replacements = [
    ('^Settings', 'Project_settings'),
    (r'^project_name = "(.*)"', r'project_name = "abc"'), # simply replaces with fixed value
    (r'^project_id = "(.*)"', r'project_id = "P-"')  # copies in the found group 1 at 
]


def replace():
    lines = []
    with open("project_properties.cfg", "r") as config:
        for line in config.readlines():
            for pair in replacements:  # apply each replacement that matches line
                line = re.sub(pair[0], pair[1], line)  # substitute found pattern with replacement
            lines.append(line)  # add each read line to the buffer (if changed or not)

    with open("project_properties_.cfg", "w") as config: # Note: used a new filename
        config.writelines(lines)


replace()

将产生所需的输出（在 project_id 处加上 inserting-replacement）：

Project_settings
######################
project_id = "P-468324678997"
project_name = "abc"

使用现有库进行解析和更新

作为OneCricketeer's answer suggests:

当您设法忽略 header 时，您将认识到 与至少两个常见 config-file 的强相似性（即 key = value 表示） ] 格式：

这将允许您研究和查找现有库，例如 Python 的 built-in configparser:

到modify an INI-file
或properties-file

Python 替换文本值正则表达式

Python replace text value regular expression

python

python-re

自动化 text-editor 的 regex-replace

使用现有库进行解析和更新