Python学习笔记之Python基础综合实践-杨辉三角

最开始接触的python的时候，杨辉三角写的复杂：

#杨辉三角

def YangHui(n):
    i = 3
    j = 1
    L_before = [1,1]
    if n < 1:
        print('ERROR!  The number must >= 1')
    elif n == 1:
        print([1])
    elif n == 2:
        print([1])
        print([1,1])

    else:
        print([1])
        print([1,1])
        while i <= n:
            L_now = [ x for x in range(i)]
            L_now[0] = 1
            L_now[i-1] = 1
            while j < i-1:
                L_now[j] = L_before[j-1] + L_before[j]
                j += 1
            i += 1
            j = 1
            L_before = L_now
            print(L_before)


n = int(input('n = '))

YangHui(n)

input('Print any key to exit!')

后来发现，还可以这么实现杨辉三角：

L = [1]
while 1:
    yield L
    L = [1] + [ L[n] + L[n+1] for n in range(len(L)-1) ]  + [1] 

真是相形见绌啊T T