41-列表类型内置方法

目录

• 一.列表类型内置方法(list)
  • 1.用途
  • 2.定义
  • 3.常用操作+内置方法
    • 3.1按索引取值
    • 3.2 切片
    • 3.3 长度
    • 3.4 成员运算 in和not in
    • 3.5 追加值
    • 3.6 删除
    • 3.7 循环
  • 4.其他操作
    • 4.1 insert()
    • 4.2 pop()
    • 4.3 remove()
    • 4.4 count()
    • 4.5 index()
    • 4.6 index()
    • 4.7 copy()
    • 4.8extend()
  • 4.存一个或多个值
  • 5.有序或无序
  • 6.可变或不可变

一.列表类型内置方法(list)

1.用途

多个装备，多个爱好，多门课程，多个朋友

2.定义

[]内可以有多个类型的值，逗号分割元素

my_hobbies =['sing','jump','rap','basketball']
print(my_hobbies)

#['sing', 'jump', 'rap', 'basketball']

l = list('hello world')
print(f'l:{l}')

#l:['h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']

3.常用操作+内置方法

3.1按索引取值

正向+反向取值，既可以存也可以取

name = ['lwx','hanye','haha']
print(name[1])
print(name[-1])
print(name[:2])

#hanye
#haha
#['lwx', 'hanye']

3.2 切片

name = ['lwx','hanye','haha','happy','hiahiahia']
print(name[0::2])

# ['lwx', 'haha', 'hiahiahia']

3.3 长度

name = ['lwx','hanye','haha','happy','hiahiahia']
print(len(name))

#5

3.4 成员运算 in和not in

name = ['lwx','hanye','haha','happy','hiahiahia']

print('lalala' not in name)
print('lwx'and 'hanye' in name)

#True
# True

3.5 追加值

name = ['lwx','hanye','haha','happy','hiahiahia']
name.append('forever')
print(name)

# ['lwx', 'hanye', 'haha', 'happy', 'hiahiahia', 'forever']=

3.6 删除

name = ['lwx','hanye','haha','happy','hiahiahia']
del name[4]
print(name)

# ['lwx', 'hanye', 'haha', 'happy']

3.7 循环

name = ['lwx','hanye','haha','happy','hiahiahia']
for i in name:
    print(i)
    
# lwx
# # hanye
# # haha
# # happy
# # hiahiahia

4.其他操作

4.1 insert()

name = ['lwx','hanye','haha','happy','hiahiahia']
name.insert(1,'like')
name.insert(3,'forever')
print(name)

# ['lwx', 'like', 'hanye', 'forever', 'haha', 'happy', 'hiahiahia']

4.2 pop()

# list之pop()，pop()默认删除最后一个元素
name = ['lwx','hanye','haha','happy','hiahiahia']
name.pop()
print(name)
name.pop(2)
print(name)

# ['lwx', 'hanye', 'haha', 'happy']
# # ['lwx', 'hanye', 'happy']

4.3 remove()

name = ['lwx','hanye','haha','happy','hiahiahia']
name.remove('hiahiahia')
print(name)

# ['lwx', 'hanye', 'haha', 'happy']

4.4 count()

name = ['lwx','hanye','haha','happy','hiahiahia','lwx','hanye']
print(name.count('hanye'))

#2

4.5 index()

name = ['lwx','hanye','haha','happy','hiahiahia','lwx','hanye']
print(name.index('haha'))

#2

4.6 index()

name = ['lwx','hanye','haha','happy','hiahiahia','lwx','hanye']
name.clear()
print(name)

#[]

4.7 copy()

name = ['lwx','hanye','haha','happy','hiahiahia']
name2= name.copy()
print(name2)

# ['lwx', 'hanye', 'haha', 'happy', 'hiahiahia']

4.8extend()

name1 = ['lwx','hanye','haha','happy','hiahiahia']
name2 = ['520']
name1.extend(name2)
print(name1)

# ['lwx', 'hanye', 'haha', 'happy', 'hiahiahia', '520']

4.存一个或多个值

用于存储多个值

5.有序或无序

列表是有序的，可以按照索引取值

hobby_list = ['read', 'run', 'girl']
print(f'first:{id(hobby_list)}')
hobby_list[2] = ''
print(f'second:{id(hobby_list)}')

# first:35552776
# second:35552776

6.可变或不可变

是可变数据类型