如何重命名列表中的标签？

Question

我有这样的文件

301 my name is joe
303 whatsup
306 how are you doing today
308 what happened?
308 going home
309 let's go

我想将标签转换301, 303, 306, 308, 308, 309为1, 2, 3, 4, 4, 5

如何以这样的方式重命名这些标签,使类似的标签得到相同的数字？

Answer 1

使用字典存储从原始标签到新标签的映射,并使用len字典的当前值来表示尚未映射的值setdefault.

>>> labels = 301, 303, 306, 308, 308, 309
>>> names = {}
>>> for l in labels:
...     names.setdefault(l, len(names)+1)
...
>>> names
{301: 1, 303: 2, 306: 3, 308: 4, 309: 5}

更完整的例子:

text = """301 my name is joe
303 whatsup
306 how are you doing today
308 what happened?
308 going home
309 let's go""".splitlines()

import re
names = {}
replacer = lambda x: str(names.setdefault(x.group(), len(names) + 1))
for line in text:
    replaced = re.sub(r'^\d+', replacer, line)
    print(replaced)

输出:

1 my name is joe
2 whatsup
3 how are you doing today
4 what happened?
4 going home
5 let's go