按点分隔字符串值的拆分对行进行排序

def split_and_sort_lines(input_string):
    lines = input_string.split('\n')  # 按行拆分字符串
    split_lines = [line.split('.') for line in lines]  # 按点拆分每行字符串
    sorted_lines = sorted(split_lines, key=lambda x: [int(num) for num in x])  # 按拆分后的值进行排序
    result = ['.'.join(line) for line in sorted_lines]  # 拼接排序后的行
    return '\n'.join(result)  # 拼接结果字符串

input_string = "1.2.3\n4.5.6\n1.2.1\n3.2.1"
output_string = split_and_sort_lines(input_string)
print(output_string)

1.2.1
1.2.3
3.2.1
4.5.6