Python初级之查找列表中重复元素

示例代码：

lstA = [4, 2, 5, 5, 6, 8, 6, 5, 2, 3, 2, 6, 2, 5, 4, 2, 3, 6, 9, 5, 2, 2, 6, 8, 2, 1, 4, 5, 6, 8, 5, 2]
setB = set(lstA)

for elB in setB:
    count = 0
    for elA in lstA:
        if elB == elA:
            count += 1
    print(elB, "的个数为:", count)

运行结果：

1 的个数为: 1
2 的个数为: 9
3 的个数为: 2
4 的个数为: 3
5 的个数为: 7
6 的个数为: 6
8 的个数为: 3
9 的个数为: 1

Process finished with exit code 0

示例代码2：

lstA = [4, 2, 5, 5, 6, 8, 6, 5, 2, 3, 2, 6, 2, 5, 4, 2, 3, 6, 9, 5, 2, 2, 6, 8, 2, 1, 4, 5, 6, 8, 5, 2]
el = lstA
from collections import defaultdict


def listDu(seq):
    allNum = defaultdict(list)
    for i, item in enumerate(seq):
        allNum[item].append(i)
    return ((key, l) for key, l in allNum.items()
            if len(l) > 1)


for elOne in sorted(listDu(el)):
    print(elOne)

运行结果：

(2, [1, 8, 10, 12, 15, 20, 21, 24, 31])
(3, [9, 16])
(4, [0, 14, 26])
(5, [2, 3, 7, 13, 19, 27, 30])
(6, [4, 6, 11, 17, 22, 28])
(8, [5, 23, 29])


Process finished with exit code 0