在量化数据处理中,常用itertools来完成数据的各类排列组合以寻找最优参数数组
1、数据准备函数
import itertools items = [1, 2, 3] ab = ['a', 'b'] cd = ['c', 'd']
#1. permutations: 考虑顺序组合元素spa
for item in itertools.permutations(items): print(item)
返回code
(1, 2, 3) (1, 3, 2) (2, 1, 3) (2, 3, 1) (3, 1, 2) (3, 2, 1)
#2. combinations,不考虑顺序,不放回数据blog
for item in itertools.combinations(items, 2): print(item)
返回it
(1, 2) (1, 3) (2, 3)
# 3. combinations_with_replacement,不考虑顺序,有放回数据io
for item in itertools.combinations_with_replacement(items, 2): print(item)
返回class
(1, 1) (1, 2) (1, 3) (2, 2) (2, 3) (3, 3)
# 4. product()函数,迪卡尔积,在参数组合中寻找最优参数import
针对ab,cd两个集合进行排列组合im
for item in itertools.product(ab, cd): print(item)
返回
('a', 'c') ('a', 'd') ('b', 'c') ('b', 'd')