Python Foundation-list

1. List creation

New_list1 = [' TV ', ' Car ', ' Cloth ', ' food ']
New_list2 = List ([' TV ', ' Car ', ' Cloth ', ' food '])
Print (NEW_LIST1)
Print (NEW_LIST2)
Operation Result:
[' TV ', ' Car ', ' Cloth ', ' food ']
[' TV ', ' Car ', ' Cloth ', ' food ']

2, list commonly used methods:

1. Append

New_list1 = [' TV ', ' Car ', ' Cloth ', ' food ']
Print (NEW_LIST1)
New_list1.append (' water ') #追加 ' water '
Print (NEW_LIST1)
Operation Result:
[' TV ', ' Car ', ' Cloth ', ' food ']
[' TV ', ' Car ', ' Cloth ', ' food ', ' water ']

2.count

New_list1 = [' TV ', ' Car ', ' Cloth ', ' food ', ' food ']
Print (New_list1.count (' food ')) #统计 ' food ' number of times in the list = 2

3.extend

New_list1 = [' TV ', ' Car ', ' Cloth ', ' food ', ' food ']
New_list1.extend ([11,22,33, ' Car '])
Print (NEW_LIST1)
Operation Result:
[' TV ', ' car ', ' Cloth ', ' food ', ' food ', one, one, $, ' car ']

4.sort

New_list1 = [' TV ', ' Car ', ' Cloth ', ' food ', ' food ']
Print (NEW_LIST1)
New_list1.sort () #正向排序
Print (NEW_LIST1)
New_list1.sort (reverse=true) #反向排序
Print (NEW_LIST1)
Operation Result:
[' TV ', ' Car ', ' Cloth ', ' food ', ' food ']
[' Car ', ' Cloth ', ' food ', ' food ', ' TV '] #正向排序结果
[' TV ', ' food ', ' food ', ' Cloth ', ' Car '] #反向排序结果

5. Len

New_list1 = [' TV ', ' Car ', ' food ', ' Cloth ', ' food ']
Print (len (new_list1)) = 5 #打印元素的个数

6.remove

New_list1 = [' TV ', ' Car ', ' food ', ' Cloth ', ' food ']

New_list1.remove (' food ')
Print (NEW_LIST1)
Operation Result:
[' TV ', ' Car ', ' Cloth ', ' food '] #remove会删除找到的第一个相同元素

7.pop

New_list1 = [' TV ', ' Car ', ' food ', ' Cloth ', ' food ']
New_list1.pop () #随机删除一个元素
Print (NEW_LIST1)
New_list1.pop (2) #指定删除某个元素
Print (NEW_LIST1)
The result of the operation is:
[' TV ', ' Car ', ' food ', ' Cloth ']
[' TV ', ' Car ', ' Cloth ']#, the 3rd element ' food ' is removed here

8.index

New_list1 = [' TV ', ' Car ', ' food ', ' Cloth ', ' food ']
Print (New_list1.index (' food ')) #返回指定元素的index值, the same element returns the first one found
Operation Result: 2

9.insert

New_list1 = [' TV ', ' Car ', ' food ', ' Cloth ', ' food ']
New_list1.insert (2, ' hahaha ') #向指定的位置插入元素
Print (NEW_LIST1)
The result of the operation is:
[' TV ', ' Car ', ' hahaha ', ' food ', ' Cloth ', ' food ']

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