python - 为什么 str.translate 在 Python 3 中不起作用？

Question

为什么 'a'.translate({'a':'b'}) 返回 'a' 而不是 'b'?我正在使用 Python 3。

Answer 1

使用的键是字符的序数，而不是字符本身:

'a'.translate({ord('a'): 'b'})

str.maketrans

使用起来更简单

>>> 'a'.translate(str.maketrans('a', 'b'))
'b'

>>> help(str.translate)
Help on method_descriptor:

translate(...)
    S.translate(table) -> str

    Return a copy of the string S, where all characters have been mapped
    through the given translation table, which must be a mapping of
    Unicode ordinals to Unicode ordinals, strings, or None.
    Unmapped characters are left untouched. Characters mapped to None
    are deleted.