Python URL获取中间字符串

import re

def get_middle_string(url, start_str, end_str):
    pattern = start_str + "(.*?)" + end_str
    result = re.search(pattern, url)
    if result:
        return result.group(1)
    else:
        return None

url = "https://www.example.com/path/middle_string/end"
start_str = "path/"
end_str = "/end"
middle_string = get_middle_string(url, start_str, end_str)
print(middle_string)

def get_middle_string(url, start_str, end_str):
    start_index = url.find(start_str) + len(start_str)
    end_index = url.rfind(end_str)
    if start_index >= 0 and end_index >= 0 and start_index < end_index:
        return url[start_index:end_index]
    else:
        return None

url = "https://www.example.com/path/middle_string/end"
start_str = "path/"
end_str = "/end"
middle_string = get_middle_string(url, start_str, end_str)
print(middle_string)