检查该字符串包含两个相同字符的方法？

Question

让我们说:

str = "Hello! My name is Barney!"

是否有一个或两个行方法来检查此字符串是否包含两个!？

Answer 1

是的,您可以count使用字符串的方法轻松地在一行中获得解决方案:

>>> # I named it 'mystr' because it is a bad practice to name a variable 'str'
>>> # Doing so overrides the built-in
>>> mystr = "Hello! My name is Barney!"
>>> mystr.count("!")
2
>>> if mystr.count("!") == 2:
...     print True
...
True
>>>
>>> # Just to explain further
>>> help(str.count)
Help on method_descriptor:

count(...)
    S.count(sub[, start[, end]]) -> int

    Return the number of non-overlapping occurrences of substring sub in
    string S[start:end].  Optional arguments start and end are
    interpreted as in slice notation.

>>>