如何遍历一个数组并创建一个列表来计算一个数字重复的次数

def count_duplicates(arr):
    count_dict = {}
    for num in arr:
        if num in count_dict:
            count_dict[num] += 1
        else:
            count_dict[num] = 1
    
    result = []
    for num, count in count_dict.items():
        result.append(f"{num}: {count}")
    
    return result

# 示例用法
arr = [1, 2, 3, 2, 1, 3, 3, 4, 5, 4]
result = count_duplicates(arr)
print(result)

['1: 2', '2: 2', '3: 3', '4: 2', '5: 1']