def triangles():
L = [1]
while True:
yield L[:]
#L+=[0]
#L = [L[i]+L[i-1] for i in range(len(L))]
# 有没有办法2行就搞定呢?
#L = [1] + [L[i]+L[i+1] for i in range(len(L)-1)] + [1]
#L = [L[i-1]+L[i] if (i is not 0) or (i is not len(L)) else 1 for i in range(len(L)+1)] #错了。。。这样会造成index溢出
L = [1 if (i is 0) or (i is len(L)) else L[i-1]+L[i] for i in range(len(L)+1)]
独孤伶俜233
emmm,有点难度的。。。