Python List &tuple

1        Listand theTuple1.1   List(ordered repeatable modifiable)

A list is an ordered set of elements that can be added and removed at any time.

>>> list=[1,2,3]

>>> List

[1, 2, 3]

>>> list=[' 1 ', ' 2 ', ' 3 ']

>>> List

[' 1 ', ' 2 ', ' 3 ']

>>> len (list)-- displays The number of elements in the list

3

>>>List[0] --the number of element indexes starts from 0 , that is, from left to right the first is 0 , and Redis Similar in

' 1 '

>>> List[1]

' 2 '

>>> List[2]

' 3 '

>>>List[-1] --The penultimate, the rightmost element , similar to Redis

' 3 '

>>> List[-2]

' 2 '

The list is a mutable, ordered table, so you can append an element to the end of the list :

>>> list.append (' 4 ')-- Note the brackets, not []

>>> List

[' 1 ', ' 2 ', ' 3 ', ' 4 ']

>>> List.append (4)

>>> List

[' 1 ', ' 2 ', ' 3 ', ' 4 ', 4]

inserts an element into the specified position , such as where the index number is 1

>>> List.insert (1, ' x ')--1 represents the index position,x represents the element

>>> List

[' 1 ', ' X ', ' 2 ', ' 3 ', ' 4 ', 4]

Delete Element , the last bit is deleted by default, and you can specify an element at a location

>>> List

[' 1 ', ' X ', ' 2 ', ' 3 ', ' 4 ', 4]

>>> List.pop ()-- Delete the last element by default

4-- returns the deleted element

>>> List

[' 1 ', ' X ', ' 2 ', ' 3 ', ' 4 ']

>>> List

[' 1 ', ' X ', ' 2 ', ' 3 ', ' 4 ']

>>> List.pop (1)-- Specify the deletion of the 1-position element

' X '

>>> List

[' 1 ', ' 2 ', ' 3 ', ' 4 ']

To replace an element with another element , you can assign a value directly to the corresponding index position

>>> List

[' 1 ', ' 2 ', ' 3 ', ' 4 ']

>>> list[0]= ' 0 '

>>> List

[' 0 ', ' 2 ', ' 3 ', ' 4 ']

List The data type of the elements inside can also be different

>>> List

[' 1 ', ' X ', ' 2 ', ' 3 ', ' 4 ', 4]

List in list

>>> List

[' 1 ', ' 2 ', ' 3 ', ' 4 ']

>>> List.insert (1,[' 1 ', ' 2 '])

>>> List

[' 1 ', [' 1 ', ' 2 '], ' 2 ', ' 3 ', ' 4 ']

>>> List[1][1]-- Some like two-dimensional arrays

' 2 '

Empty List

>>> l=[]

>>> Len (L)

0

1.2   Tuple(orderly, repeatable, non-modifiable)

It is also an ordered list,and the tuple and list are very similar, but the tuple cannot be modified once initialized.

>>> (t=)

>>> T

(1, 2)

>>> t= ()-- empty tuple

>>> Len (t)

0

when there is only one element in a tuple, the definition takes a comma

>>> t= (1,)

>>> T

(1,)

>>> T[0]

1

Create a "variable" tuple

>>> t= (1,2,[1,2])

>>> t[2][0]= ' x '

>>> t[2][1]= ' y '

>>> T

(1, 2, [' X ', ' Y '])

This article is from the "90SirDB" blog, be sure to keep this source http://90sirdb.blog.51cto.com/8713279/1795431

Python List &tuple