如何在模式搜索中替换字符串变量

import re

def replace_variables(pattern, variables):
    # 使用正则表达式匹配需要替换的字符串变量
    matches = re.findall(r'\{(\w+)\}', pattern)
    
    # 遍历匹配结果，替换字符串变量
    for match in matches:
        if match in variables:
            pattern = pattern.replace("{" + match + "}", variables[match])
    
    return pattern

# 示例用法
pattern = "Hello, {name}! Today is {day}."
variables = {
    "name": "John",
    "day": "Monday"
}

result = replace_variables(pattern, variables)
print(result)