list list

Like str int, it is a class, a basic data type

1. Representation method : The list is generally represented by [], and all classes can be put into the list, such as:

a = []
b = ['dsfn','123','Hahaha']
c = ['capture',['fdjgo','Chinese'],123456789]

When there are both strings and numbers in a list, we have to write a loop to splicing them,
but when there are only strings, we can just use the join method to splicing

2. Add, delete, modify and check the list

lst = [11,22,33,44]

a. to increase

.append() (append element)	Append an element to the end of a list
.extend() (the specified iterable)	Splits a specified iterable into individual elements and appends them to the end of the list
.insert() (specified location, specified content)	Insert the specified content into the specified position of the list, for example, specify '0' to insert the top of the list

For example, lst.extend('Do whatever you want'), the last thing added to the list is 'the four elements after splitting "Do whatever you want"'

b. delete

from to[1]	delete the specified element by index
.clear()	clear all elements in the list
.pop() (specified position, default is last)	Delete the element at the specified position in the list and return the value after deletion
.remove() (specified content)	Match the specified content with the elements in the list from left to right, and delete the same if it matches (only delete the first element that matches)

c. Modify

可以通过直接赋值的方式给列表中的元素进行修改，例如：a[1] = 99 ，或者，a[1:4] = 23,'asdf',456

d.查询

通过切片，指定索引来查询列表中指定位置的元素
可以通过print()接上元素，切片，for和while循环获取

3.列表list的其它方法

.copy()	将一个列表复制到另一个列表，这里的复制指的是浅复制
.count() (指定的元素)	计算指定的元素在列表中出现的次数
.index() (指定的元素，起始位置，结束位置)	从左到右寻找指定元素在范围内的索引位置(只寻找一次)
.reverse()	将列表中的元素反转 (比如[11,22,33]反转为[33,22,11])
.sort() (要排序的列表，特定的顺序，以及...)	将列表按照指定的顺序排序（这个函数稍复杂我会开辟一个单独的文章进行说明）

python list list learning summary