使用python统计字符串中重复字符个数

可以使用字典来记录每个字符出现的次数，然后遍历字符串并更新字典。最后，将字典中值大于1的键值对统计即可。下面是示例代码：

def count_duplicate_chars(s):
    freq = {}
    for c in s:
        freq[c] = freq.get(c, 0) + 1
    count = 0
    for k, v in freq.items():
        if v > 1:
            count += 1
    return count

使用示例：

s = "hello world"
duplicate_count = count_duplicate_chars(s)
print(f"There are {duplicate_count} duplicate characters in '{s}'")
# 输出：There are 3 duplicate characters in 'hello world'