python统计列表中重复元素的出现次数

1.用count()函数（对字符串列表元组进行计数）

list_japan = [1,2,3,4,5,4,3,5,2,2]
for i in set(list_japan):
		#count函数某一个字符在列表中的出现次数
    print(f"{i}出现{list_japan.count(i)}次")

2.用Counter类（对字符串列表元组字典进行计数）

list_japan = [1,2,3,4,5,4,3,5,2,2]
from collections import Counter
# 对字符串列表元祖字典进行计数,返回一个字典类型的数据,键是元素,值是元素出现的次数
print(Counter(list_japan))

python字典中不允许同一个键出现两次。创建时如果同一个键被赋值两次，后一个值会被记住
3.用双层循环计数

list_japan =[1,4,2,4,2,2,5,2,6,3,3,6,3,6,6,3,3,3,7,8,9,8,7,0,7,1,2,4,7,8,9]

dicc = {}
count = 0
for i in set(list_japan):
    for j in list_japan:
        if i==j:
            count+=1
    dicc[i]=count
    count=0
print(dicc)