用Python编写一个程序 生成包含1000 个随机字符的字符串，统计每个字符的出现次数

import random

# 生成包含1000个随机字符的字符串
str_list = [chr(random.randint(97, 122)) for i in range(1000)]
str = ''.join(str_list)

# 统计每个字符的出现次数
char_dict = {}
for char in str:
    if char in char_dict:
        char_dict[char] += 1
    else:
        char_dict[char] = 1

# 输出结果
for key, value in char_dict.items():
    print(key, ':', value)