排列組合
基本排列
123的排列組合有 123 132 213 231 312 321
WARNING
順序是有差的
程式碼
python
def permutations(nums):
if len(nums) == 1:
yield nums
else:
for i in range(len(nums)):
for j in permutations(nums[:i] + nums[i+1:]):
yield [nums[i]] + j
nums = [1, 2, 3]
a = list(permutations(nums))
print(a)條件排列
希望 ['肉', '菜', '蛋', '果']
變成
('肉', '菜'), ('肉', '蛋'), ('肉', '果') , ('菜', '蛋'), ('菜', '果'), ('蛋', '果')
程式碼
python
def combinations(nums, r):
if r == 1:
for i in nums:
yield [i]
else:
for i in range(len(nums)):
for j in combinations(nums[i+1:], r-1):
yield [nums[i]] + j
nums = [1, 2, 3]
a = list(combinations(nums, 2))
print(a)itertools 高級迭帶器
可以自己寫,但也可以引用別人己經做好的 連結
Contributors
lucashsu95