Python:列表中语法正确的可读字符串(用牛津逗号)

此函数的工作原理是处理小列表与处理大列表不同。

from typing import Any, List

def readable_list(seq: List[Any]) -> str:
    """Return a grammatically correct human readable string (with an Oxford comma)."""
    # Ref: https://stackoverflow.com/a/53981846/
    seq = [str(s) for s in seq]
    if len(seq) < 3:
        return ' and '.join(seq)
    return ', '.join(seq[:-1]) + ', and ' + seq[-1]

用法示例:

readable_list([])
''

readable_list(['A'])
'A'

readable_list(['A', 2])
'A and 2'

readable_list(['A', None, 'C'])
'A, None, and C'

readable_list(['A', 'B,B', 'C,C,C'])
'A, B,B, and C,C,C'

readable_list(['A', 'B', 'C', 'D'])
'A, B, C, and D'

您也可以使用解包进行 清洁剂溶液:

def readable_list(_s):
  if len(_s) < 3:
    return ' and '.join(map(str, _s))
  *a, b = _s
  return f"{', '.join(map(str, a))}, and {b}"

vals = [[], ['A'], ['A', 2], ['A', None, 'C'], ['A', 'B,B', 'C,C,C'], ['A', 'B', 'C', 'D']]
print([readable_list(i) for i in vals])

输出:

['', 'A', 'A and 2', 'A, None, and C', 'A, B,B, and C,C,C', 'A, B, C, and D']

我真的很固执,我真的很想找出一个线性解决方案。

"{} and {}".format(seq[0], seq[1]) if len(seq)==2 else ', '.join([str(x) if (y < len(seq)-1 or len(seq)<=1) else "and {}".format(str(x)) for x, y in zip(seq, range(len(seq)))])

编辑
我觉得这个很管用。我认为这个问题也比我想象的要复杂得多,用一条不难看的线就能解决。

基于 accepted answer 对于 thread you linked to ,这里有一个单行线,它接受一个可选的参数来决定是否使用牛津逗号。

from typing import List

def list_items_in_english(l: List[str], oxford_comma: bool = True) -> str:
    """
    Produce a list of the items formatted as they would be in an English sentence.
    So one item returns just the item, passing two items returns "item1 and item2" and
    three returns "item1, item2, and item3" with an optional Oxford comma.
    """
    return ", ".join(l[:-2] + [((oxford_comma and len(l) != 2) * ',' + " and ").join(l[-2:])])