【LeetCode】Jewels and Stones

題目：

You're given strings J representing the types of stones that are jewels, and S representing the stones you have.  Each character in S is a type of stone you have.  You want to know how many of the stones you have are also jewels.

The letters in J are guaranteed distinct, and all characters in J and S are letters. Letters are case sensitive, so "a" is considered a different type of stone from "A".

Example 1:

Input: J = "aA", S = "aAAbbbb"

Output: 3

Example 2:

Input: J = "z", S = "ZZ"

Output: 0

Note:

S and J will consist of letters and have length at most 50.

The characters in J are distinct.（J中字元是不重複的）

 

答案：

class Solution(object):
    def numJewelsInStones(self, J, S):
        """
        :type J: str
        :type S: str
        :rtype: int
        """
        return(sum(s in J for s in S))

利用迭代器和生成器，判斷S中的字元s是否在J中，是為True，否則為False

print sum([True,False,True])的結果是2