2020-02-10 18:54:06
杨辉三角定义如下：
1
/
1 1
/ /
1 2 1
/ / /
1 3 3 1
/ / / /
1 4 6 4 1
/ / / / /
1 5 10 10 5 1
把每一行看做一个list，试写一个generator，不断输出下一行的list
1 def triangles(): 2 i=1 3 list1=[1] 4 yield list1 5 i=2 6 list2=[1,1] 7 yield list2 8 list1=list2 9 while i<=10: 10 i+=1 11 list2=[0 for i in range(0,i)] 12 list2[0]=1 13 list2[-1]=1 14 for j in range(1,i-1): 15 list2[j]=list1[j-1]+list1[j] 16 list1=list2 17 yield list2 18
测试代码
1 # 期待输出: 2 # [1] 3 # [1, 1] 4 # [1, 2, 1] 5 # [1, 3, 3, 1] 6 # [1, 4, 6, 4, 1] 7 # [1, 5, 10, 10, 5, 1] 8 # [1, 6, 15, 20, 15, 6, 1] 9 # [1, 7, 21, 35, 35, 21, 7, 1] 10 # [1, 8, 28, 56, 70, 56, 28, 8, 1] 11 # [1, 9, 36, 84, 126, 126, 84, 36, 9, 1] 12 n = 0 13 results = [] 14 for t in triangles(): 15 results.append(t) 16 n = n + 1 17 if n == 10: 18 break 19 20 for t in results: 21 print(t) 22 23 if results == [ 24 [1], 25 [1, 1], 26 [1, 2, 1], 27 [1, 3, 3, 1], 28 [1, 4, 6, 4, 1], 29 [1, 5, 10, 10, 5, 1], 30 [1, 6, 15, 20, 15, 6, 1], 31 [1, 7, 21, 35, 35, 21, 7, 1], 32 [1, 8, 28, 56, 70, 56, 28, 8, 1], 33 [1, 9, 36, 84, 126, 126, 84, 36, 9, 1] 34 ]: 35 print('测试通过!') 36 else: 37 print('测试失败!')