20180128
1.计算一个四乘四矩阵的所有元素的和,以及对角线之和
[
[1,2,3,4],
[5,6,7,8],
[9,10,11,12],
[13,14,15,16]
]
#encoding=utf-8 a=[ [1,2,3,4], [5,6,7,8], [9,10,11,12], [13,14,15,16] ] #反对角线的规律 #03 #12 #21 #30 #矩阵的反对角线之和 count=0 for i in a: print i for j in i: count+=j print count #矩阵的正对角线之和 count=0 for i in range(len(a)): count+=a[i][i] print count #矩阵所有元素之和 count=0 for i in range(len(a)): count+=a[i][len(a)-1-i] print count
2.输入数组,最大的与第一个元素交换,最小的与最后一个元素交换,输出数组。
a=[] while 1: try: user_input = raw_input("pleaser input a number:") if user_input.strip() =="over": break else: a.append(int(user_input)) except: print "error ,try again!" max_num = max(a) min_num = min(a) max_num_index = a.index(max_num) min_num_index = a.index(min_num) a[0],a[max_num_index]=a[max_num_index],a[0] a[-1],a[min_num_index]=a[min_num_index],a[-1] print a3.有n个整数,使其前面各数顺序向后移m个位置,最后m个数变成最前面的m个数
a=[1,2,3,4,5,6,7] m=3 last_m_numbers=a[-m:] front_numbers=a[:-1-m+1] print last_m_numbers+front_numbers