python基础之操作列表

遍历元素

magicians = ['alice','david','carolina']
for magician in magicians:
	print(magician)

magicians = ['alice','david','carolina']
for magician in magicians:
	print(magician.title() + ", that was a great trick")
print("Thank you, everyone. That was a great magic show")

遍历数字

range()生成一系列数字

for value in range(1,5):
	print(value)

创建数字列表

number = list(range(1,6))
print(number)

number = list(range(2,11,2))   #创建从2开始相差为2的数字并不超过11
print(number)

squares = []
for value in range(1,11):
	square = value ** 2   #平方数
	squares.append(square)
print(squares)

数字列表统计

digits = [1,2,3,4,5,6,7,8,9,0]
print(min(digits))    #最小值
print(max(digits))    #最大值
print(sum(digits))    #求和值

列表解析

squares = [value**2 for value in range(1,11)]
print(squares)

切片

注意：数字是从0开始数

players = ['charles','martina','michael','florence','eli']
print(players[0:3])  #从第一个到第三个

players = ['charles','martina','michael','florence','eli']
print(players[:3])  #从第一个到第三个

players = ['charles','martina','michael','florence','eli']
print(players[2:])   #从第三个到最后一个

players = ['charles','martina','michael','florence','eli']
print(players[-3:])   #输出最后三个数字

url = list("0123456789")
print(url[0:10:2])  # 指定正序的间隔为2
print(url[-1:-10:-2]) #指定倒序的间隔为2
print(url[::-1])  # 倒序
print(url[-3:-1])  # 使用负数切片

遍历切片

players = ['charles','martina','michael','florence','eli']
for player in players[:3]:
	print(player)

复制列表

my_foods = ['pizza','falafel','carrot cake']
friend_foods = my_foods[:]
my_foods.append('cannoli')
friend_foods.append('ice cream')
print(my_foods)
print(friend_foods)

注意：

my_foods = ['pizza','falafel','carrot cake']
friend_foods = my_foods   #不能这样直接赋值
my_foods.append('cannoli')
friend_foods.append('ice cream')
print(my_foods)
print(friend_foods)

遍历元组

元组是不能修改的列表，因此不能随意更改元组里的元素

dimensions = (200,50)
for dimension in dimensions:
	print(dimension)

元组赋值

虽然不能修改元组的元素，但可以给元组的变量赋值

dimensions = (200,50)
for dimension in dimensions:
	print(dimension)

dimensions = (400,100)
for dimension in dimensions:
	print(dimension)