python 语法糖

把列表中的正数和负数分开排列.

lst = [1, -2, 10, -11, 123, -124]
lst.sort(key=lambda x: (x < 0, abs(x)))
print(lst)
[1, 10, 123, -2, -11, -124]

把多维列表转为一维列表

list_1 = [[1, 2], [3, 4, 5], [6, 7], [8], [9]]
# function 1
print([i for k in list_1 for i in k])
# function 2
print(sum(list_1, []))

查询列表中相同元素的个数

from collections import Counter

a = [1, 1, 1, 1, 1, 2, 2, 2, 3, 4, 4, 4, 5,9]
a_count = Counter(a)
print(a_count)

b = ['hinimix', 'hinimix', 'hinimix', 'reaphix', 'cui', 'reaphix']
b_count = Counter(b)
print(b_count)

列表去重

datas =[1,2,3,2,1,4,5,2,5,6,7,8,9,0]
datas = list(set(datas))
print(datas)