列表类型内置方法

列表类型内置方法

一、列表（list）

描述多个爱好，多门课程

1.2 定义方式

在[]内可以有多个任意类型的值，逗号分隔元素

hobby_list = ['run','read','trip','music']
print(f"hobby_list:{hobby_list}")
--------------------------------------------------------
hobby_list:['run', 'read', 'trip', 'music']

1.3 内置方法

1.3.1优先掌握

1.按索引取值

hobby_list = ['run','read','trip','music']
print(f"hobby_list:{hobby_list[0]}")
---------------------------------------------------------
hobby_list:run

2.切片

hobby_list = ['run','read','trip','music']
print(f"hobby_list:{hobby_list[0:3:2]}")
----------------------------------------------------------
hobby_list:['run', 'trip']

3.长度

hobby_list = ['run','read','trip','music']
print(f"hobby_list:{len(hobby_list)}")
-----------------------------------------------------
hobby:4

4.in和not in

hobby_list = ['run','read','trip','music']
print(f"run in hobby_list:{'run'in hobby_list}")
print(f"run not in hobby_list:{'run' not in hobby_list}")
---------------------------------------------------------
run in hobby_list:True
run not in hobby_list:False

5.for循环

hobby_list = ['run','read','trip','music']
for i in hobby_list:
    print(i)
------------------------------------------------------
run
read
trip
music

6.追加值

hobby_list = ['run','read','trip','music']
hobby_list.append('eat')
print(f"hobby_list:{hobby_list}")
------------------------------------------------------
hobby_list:['run', 'read', 'trip', 'music', 'eat']

7.删除

hobby_list = ['run','read','trip','music']
del hobby_list[2]
print(f"hobby:{hobby}")
---------------------------------------------------------
hobby_list:['run', 'read', 'music']

1.3.需要掌握

1.insert()

hobby_list = ['run','read','trip','music']
hobby_list.insert(1,'jiayi')
print(f"hobby_list:{hobby_list}")

2.pop():默认删除最后一个元素，如果括号里面有要求删除的元素，则删除要求删除的元素

hobby_list = ['run','read','trip','music']
hobby_list.pop(1)
print(f"hobby_list:{hobby_list}")
-------------------------------------------------------
hobby_list:['run', 'jiayi', 'read', 'trip', 'music']

3.remove()

hobby_list = ['run','read','trip','music']
hobby_list.remove('run')
print(f"hobby_list:{hobby_list}")
---------------------------------------------------------
hobby_list:['read', 'trip', 'music']

4.count()

hobby_list = ['run','read','trip','music']
print(f"hobby_list.count('run):{hobby_list.count('run')}")    #查找run在列表中的次数
---------------------------------------------------------
hobby_list.count('run):1

5.index()

hobby_list = ['run','read','trip','music']
print(f"hobby_list.index('run'):{hobby_list.index('run')}")   #查找run在列表中第一次出现的位置
---------------------------------------------------------
hobby_list('run'):0

6.clear()

hobby_list = ['run','read','trip','music']
hobby_list.clear()
print(f"hobby_list.clear:{hobby_list}")
---------------------------------------------------------
hobby_list.clear:[]

7.copy()

hobby_list = ['run','read','trip','music']
print(f"hobby_list.copy():{hobby_list.copy()}")
------------------------------------------------------------
hobby_list.copy():['run', 'read', 'trip', 'music']

8.extend()

hobby_list = ['run','read','trip','music']
hobby1 = ['jiayi','xiaoyu']
hobby_list.extend(hobby1)
print(f"hobby_list.extend():{hobby_list}")
---------------------------------------------------------
hobby_list.extend():['run', 'read', 'trip', 'music', 'jiayi', 'xiaoyu']

9.reverse()

hobby_list = ['run','read','trip','music']
hobby_list.reverse()
print(f"hobby.reverse():{hobby_list}")
---------------------------------------------------------
hobby_list.reverse():['music', 'trip', 'read', 'run']

10.sort():使用sort列表的元素必须是同类的

hobby_list = ['run','read','trip','music']
hobby_list.sort()
print(f"hobby_list{hobby_list}")
hobby_list.reverse()
print(f"hobby_list.reverse():{hobby_list}")
--------------------------------------------------------
hobby_list['music', 'read', 'run', 'trip']
hobby_list.reverse():['trip', 'run', 'read', 'music']

1.4 有一个值还是多个值

多个值

1.5 有序（索引）or无序（索引）

有序

1.6 可变or不可变

可变

hobby = ['run','read','trip','music']
print(id(hobby))
hobby2 = ''
print(id(hobby))