List introduction in Python

The list is python One of the data types in , Keywords are list. list （list） Is a variable sequence type , We can add 、 Insert 、 Delete and Replace the elements in the list .

How to create a list ：

1、 Use list function

2、 Use [] Specify a specific element list

print(list('hello world')) # ['h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']
print([1, 3, 5, 7, 9]) # [1, 3, 5, 7, 9]

Add elements to the list ：

1、 Use append() Method to add a single element

2、 Use extend() Method or operator + Batch add multiple

a = [1,2,3]
print(a.append(4)) #None append Function return value is null
print(a) # [1, 2, 3, 4]
b = [4,5,6]
a.extend(b) #None extend Function return value is null
print(a) # [1, 2, 3, 4, 4, 5, 6]
c = ['a','b','c']
print(a+c) # [1, 2, 3, 4, 4, 5, 6, 'a', 'b', 'c']

List inserts elements ：

list.insert(index,value)

a = [1,2,3]
a.insert(0, 'abcd') # insert Function has no return value
print(a)

Replace list elements ：

a = [1,2,3]
a[0]='123'
print(a)

Delete list elements ：

pop() Delete the last element , This method has a return value , Returns the value of the deleted element

remove(xxx): Delete the first match in the list xxx The elements of

summary ：