打印字符串中出现的字母的数量

def count_letters(string):
    letter_count = {}
    for char in string:
        if char.isalpha():
            if char in letter_count:
                letter_count[char] += 1
            else:
                letter_count[char] = 1
    
    for letter, count in letter_count.items():
        print(f"{letter}: {count}")

# 示例用法
count_letters("Hello, World!")

H: 1
e: 1
l: 3
o: 2
W: 1
r: 1
d: 1