按找到的第一个子字符串拆分字符串

def split_by_first_substring(s, sub):
    """
    按找到的第一个子字符串拆分字符串
    :param s: 原始字符串
    :param sub: 用作分隔符的子字符串
    :return: 拆分后的字符串列表
    """
    index = s.find(sub)
    if index == -1:
        return [s]
    return [s[:index], s[index + len(sub):]]

# 示例用法
original_string = "Hello, this is a test. This is another test."
delimiter = "is"
result = split_by_first_substring(original_string, delimiter)
print(result)  # 输出: ['Hello, th', '  a test. This is another test.']

def split_by_first_substring(s, sub):
    index = s.find(sub)
    if index == -1:
        return [s]  # 如果未找到分隔符，直接返回原始字符串
    return [s[:index], s[index + len(sub):]]