列表

可重复
类型可不同
可新增
可删除

1 创建

1、foodList = ["apple", "orange", "banana",["apple", "orange", "banana"]]
print(foodList)
print(foodList)
print(type(foodList))
print(isinstance(foodList, list))

2、list1 = []
3、list2 = list()
strval = "ppython"
4、listword = list(strval)
print(listword)

2 列表的索引和切片

1、角标

foodList = ["apple", "orange", "banana",["apple", "orange", "banana"]]
print(foodList[0])
print(foodList[-1])
print(foodList[-1][0])
print(foodList[0:2])

3 循环和遍历

foodList = ["apple", "orange", "banana",["apple", "orange", "banana"]]
#for 循环
for food in foodList:
    print(food)
#while 循环
num  = len(foodList)
i = 0
while i < num:
    print(foodList[i])
    i += 1

嵌套循环

for i,f in enumerate(foodList):
    print(i,f)
    if(isinstance(f,list)):
        for j in f:
            print(j)

增 删 改 查

增：

print(dir(list))

books = []
1、books.append('python')
books.append('java')
books.append('c++')
print(books)
2、books.insert(0,'java')
print(books)
3、books.extend('东方')
books.extend('123')
print(books)

['python', 'java', 'c++']
['java', 'python', 'java', 'c++']
['java', 'python', 'java', 'c++', '东', '方', '1', '2', '3']

改： 根据索引

books = []
books.append('python')
books.append('java')
print(books)
books[0] = '西方'
print(books)

['python', 'java']
['西方', 'java']
查：
in
not in
count
index

books = []
books.append('python')
books.append('java')
print(books)
books[0] = '西方'
print(books)
if 'java' in books:
    print('java在列表中')
if 'c++' not in books:
    print('c++不在列表中')
num = books.index('java')
print(num)
c = books.count('java')
print(c)

['python', 'java']
['西方', 'java']
java在列表中
c++不在列表中
1
1

删：
del 根据索引查询
pop 删除最后一个元素
remove 根据元素的值 进行删除

books = []
books.append('python')
books.append('java')
books.append('c++')

books.insert(0,'java')
print(books)
del books[0]
print(books)
books.pop()
print(books)
books.remove('java')
print(books)

['java', 'python', 'java', 'c++']
['python', 'java', 'c++']
['python', 'java']
['python']

排序

sort list排序，默认由小到大，reverse = true 可以由大到小
reverse list 逆置

l_v = [10,3,12,88,56,33]
print(l_v)
l_v.sort()
print(l_v)
l_v.sort(reverse=True)
print(l_v)
l_v.reverse()
print(l_v)

[10, 3, 12, 88, 56, 33]
[3, 10, 12, 33, 56, 88]
[88, 56, 33, 12, 10, 3]
[3, 10, 12, 33, 56, 88].

复制---深拷贝

copy

books = []
books.append('python')
books.append('java')
books.append('c++')
ns = books.copy()
print(ns)
print(id(books))
print(id(ns))

['python', 'java', 'c++']
4533700800
4533835968

列表是可变类型

列表是可变类型
字符串是不可变类型

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