pythondemo/tri.py

def triangles(x, y):
    if y == 1 or y == x: # y=1或y=x时，函数返回值为1
        return 1
    else:
        z = triangles(x-1, y-1) + triangles(x-1, y) # y为其他值时的递推公式
        return z
if __name__ == "__main__":
    n = int(input("请输入杨辉三角的行数："))
    for i in range(1, n+1): # 输出n行
        for j in range(0, n-i+1):
            print("   ", end=" ")
        for j in range(1, i+1):
            # 调用递归函数，输出第i行的第j个值
            print("%6d  " %(triangles(i, j)), end=" ")
        print()