python面试编程题

1：已知字符串 str= 'skdaskerkjsalkj'，请统计该字符串中各字母出现的次数

　思路是：用字典

str='skdaskerkjsalkj'
a=dict()
for i in str:
    if i not in a.keys():
        a[i]=1
    else:
        a[i]=a[i]+1
print(a)