统计字符串中字符出现的次数(Python版)

字符串转list

s = 'aabbccd'
list1 = list(s)

方法一：

list1 = ['a', 'a', 'b', 'c', 'c', 'c', 'c']
dict_cnt = {}
for value in list1:
    dict_cnt[value] = dict_cnt.get(value, 0) + 1
print(dict_cnt)

方法二：

list1 = ['a', 'a', 'b', 'c', 'c', 'c', 'c']
dict_cnt = {}
for item in list1:
    if item in dict_cnt:  # 直接判断key在不在字典中
        dict_cnt[item] += 1
    else:
        dict_cnt[item] = 1
print(dict_cnt)