Python list tuple dictionary

First, List

A set of ordered items. variable data type "can be added and censored"

A list is a collection of data surrounded by square brackets "[]", with different members separated by ",".

The list can contain any data type, or it can contain another list

Lists can access members by ordinal

Common list operations:

List.append () Append member, member data

List.pop () Delete Members, delete member I

List.count (x) calculates the number of occurrences of the parameter X in the list

List.remove () Remove members from list, delete members directly I

List.extend (l) Append another list to the list L

List.reverse () Reverses the order of the members in the list

List.index (x) Gets the position of the parameter X in the list

List.sort () sort the members in the list

List.insert () inserting data into the list insert (A, B) inserts data into the list

Two, the meta-group

Immutable Sequences

A tuple is a collection of data surrounded by parentheses "()", with different members separated by ","

Unlike lists: the data in a tuple cannot be changed once it is established

Access by subscript

Statement:

L= (a)

Tuples with 0 elements: L = ()

Tuples with 1 elements: l= (1,) note a comma

Third, the dictionary

A collection of key-value pairs (map)

A dictionary is a collection of data surrounded by curly braces "{}"

Differences from lists: Dictionaries are unordered , and members are accessed through keys in the dictionary.

The dictionary is mutable and can contain any other type

Statement:

M={K1:V1,K2:V2}

Access M[K1] will get V1

Common Dictionary operations:

Dic.clear () Empty dictionary

Dic.keys () Get a list of keys

Dic.values () Get a list of values

Dic.copy () Copy Dictionary

Dic.pop (k) Delete key k

Dic.get (k) Gets the value of the key K

Dic.update () Update member, if member does not exist, equivalent to join

Dic.items () Gets a list of keys and values

Dic.popitem

Python list tuple dictionary