Python入门day02(List)

列表简单操作

a = ["一","二","三"]

print(a)

#.insert(n,m)在列表下标n位置插入m
a.insert(0,'零')
print(a)
#['零', '一', '二', '三']


#del a[n]按下标n删除元素
del a[0]
print(a)
#['一', '二', '三']


#.pop(n)按下标弹出删除元素，可使用,不写n时弹出末尾元素
b = a.pop()
print(b)
#['三']
print(a)
#['一', '二']
a.pop(0)
print(a)
#['二']


a = ["一","二","三"]
#.remove(m)按值m删除元素
a.remove('三')
print(a)
#['一', '二']

列表排序

a = ['b','c','a','d','a']

#.sort()改变原列表排序排序
#1.升序
a.sort()
print(a)
#['a', 'a', 'b', 'c', 'd']

#2.降序
a.sort(reverse = True)
print(a)
#['d', 'c', 'b', 'a', 'a']


a = ['b','c','a','d','a']
#sort(a)不影响原列表顺序的排序
#1.升序
print(sorted(a))
#['a', 'a', 'b', 'c', 'd']
print(a)
#['b','c','a','d','a']

#2.降序
print(sorted(a,reverse = True))
#['d', 'c', 'b', 'a', 'a']
print(a)
#['b','c','a','d','a']



#.reverse()反转列表
a.reverse()
print(a)
#必须先反转再输出，分两步写
#['a', 'd', 'a', 'c', 'b']

列表创建,复制,max

#max(a),min(a),sum(a)找出a列表中最大最小值和和
print(max(a),end = ' ')
print(min(a),end = ' ')
print(sum(a))
#9 1 45


#列表解析
#创建一个1~10的列表
num = [i for i in range(1,11)]
print(num)
##[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]


#复制列表
#1. a = b[:],此时a,b指向元素相同的不同列表,改变a不影响b
food = num[:]
print(food)

food.append(11)
print(food)
#[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]
print(num)
#[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

#2.a = b,此时a,b指向同一列表,改变a的同时b也会变
food = num
print(food)
print(num)
#[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
#[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
food.append('11')
print(food)
print(num)
#[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, '11']
#[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, '11']