list基本操作_2

创建数字列表

for value in range(1,5):
    print(value,end=" ")#1 2 3 4
print()
#使用range可以生成一个指定范围的数字集合
numbers = list(range(2,7))
print(numbers)#[2, 3, 4, 5, 6]
#使用range也可以指定步长来生成数字集合
numbers = list(range(2,10,2))
print(numbers)#[2, 4, 6, 8]步长是2
#使用**2来实现一个数的平方
lst = list()
for value in range(1,11):
    lst.append(value**2)
print(lst)#[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

#对数字列表进行简单地统计计算
lst = list()
for value in range(1,11):
    lst.append(value**2)
print(min(lst))#1
print(max(lst))#100
print(sum(lst))#385

#利用解析来创建列表，将for循环和平方写成一行
lst = list([value ** 2 for value in range(1,11)])
print(lst) #[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

#列表的切片
lst = list(value ** 2 for value in range(1,11))#[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
print(lst[2:5]) #[9, 16, 25],从索引值2开始，打印到索引值位4的部分
print(lst[:5]) #[1, 4, 9, 16, 25] 默认是从索引值0开始的
print(lst[2:]) #[9, 16, 25, 36, 49, 64, 81, 100]默认是打到最后
#负数索引返回距离列表相应距离的元素
print(lst[-3:]) #[64, 81, 100]
print(lst[:-3]) #[1, 4, 9, 16, 25, 36, 49]

#如果要遍历部分切片，可以在for循环内部写上切片
for value in lst[2:9:2]:
    print(value,end=" ")

#列表的复制,切记不要直接使用myFrinedFoof = myFood
myFood = ["pizza","falafel","carrot cake"]
myFrinedFoof = myFood[:]

myFood.append("apple") #['pizza', 'falafel', 'carrot cake', 'apple']
myFrinedFoof.append("banana") #['pizza', 'falafel', 'carrot cake', 'banana']
print(myFrinedFoof)
print(myFood)

#if和列表的结合应用
avaliable_toppings = ["mushroom","oLive","green peppers",
                      "pepperoni","pineapple","extra cheese"]
requested_toppings = ["mushroom","french fries","extra cheese"]
for requested_topping in requested_toppings:
    if requested_topping in avaliable_toppings:
        print("Adding " + requested_topping + ".")
    else:
        print("Sorry , We don't have " + requested_topping + "." )