import re


def match_case(word):
    def replace(m):
        text_group = m.group()
        if text_group.isupper():
            return word.upper()
        elif text_group.islower():
            return word.lower()
        elif text_group[0].isupper():
            return word.capitalize()
        else
 
:
            return word

    return replace


if __name__ == '__main__':
    text = 'UPPER PYTHON, lower python, Mixed Python'
    test_upper = re.findall("python", text, flags=re.IGNORECASE)
    # print(test_upper)
    test_upper_1 = re.sub("python", "test", text, flags=re.IGNORECASE)
    # print(test_upper_1)
 

    test_upper_2 = re.sub("python", match_case("test"), text, flags=re.IGNORECASE)
    print(test_upper_2)

兩種函式的巢狀使用