list_practice

"""
关于列表的基本操作
"""

list1 = ["中国", "美国", 1997, 2001]
list2 = ["中国", "美国", 1997, 2001]

#1.删除元素的三种方法
del list1[2]
print("After deleting a value:")
print(list1)
list1 = list2

list1.remove(1997)
print("After deleting a value:")
print(list1)
list1 = list2

list1.pop(2)
list1.pop() #默认删除最后一个元素
print("After deleting two values:")
print(list1)

#2.添加列表元素
list1.append(2003)
print("After appending an element:")
print(list1)

#3.定义多维列表
rows = 3
cols=4
matrix = [[0 for col in range(cols)] for row in range(rows)]
for i in range(rows):
  for j in range(cols):
		matrix[i][j] = i* 3 + j
		print(matrix[i][j], end = ',')
	print('\n')
"""
输出结果：
0,1,2,3,
3,4,5,6,
6,7,8,9,
"""

#4.输出10以内偶数的平方列表
list3 = [x*x for x in range(1, 11) if x*x%2 == 0]

#5.列表生成式使用两层循环
print([m+n for m in 'ABC' for n in 'XYZ'])

#6.for循环可以同时使用两个甚至多个变量