分别统计一个字符串中的多个字符

Count multiple characters in a string separately

我的老师让我写一个函数,通过使用另一个字符串的字母来计算一个字符串的出现次数。例如:

>>>problem3("all is quiet on the western front", "tqe")
>>>["t=4", "q=1", "e=4"]

然而我只能做到:

>>>problem3("all is quiet on the western front", "tqe")
>>>[4, 1, 4]

这是我的代码:

def problem3(myString, charString):
    return [myString.count(x) for x in (charString)]

我如何获得这种格式的 ["t=4"、"q=1"、"e=4"]?

所以你只是被要求非常具体地格式化它并且你很接近,只需要格式化结果:

def problem3(myString, charString):
    return ['{}={}'.format(x, myString.count(x)) for x in charString]

>>> problem3("all is quiet on the western front", "tqe")
['t=4', 'q=1', 'e=4']