Python Language Dictionary: Difference between revisions
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or it can be populated with values: | or it can be populated with values: | ||
<syntaxhighlight lang='python'> | <syntaxhighlight lang='python'> | ||
d = {'a':'b', 1:2, true:"this is true"} | d = {'a': 'b', 1: 2, true: "this is true"} | ||
</syntaxhighlight> | </syntaxhighlight> | ||
It is good form to insert a space after <code>:</code>. | |||
=Access a Dictionary= | =Access a Dictionary= | ||
Revision as of 19:55, 16 February 2022
Internal
Overview
A dictionary is a mutable collection of key-value pairs. The pairs can be accessed and modified. Each key is unique within the key set, and can be an instance of any immutable type: boolean, integer, float, tuple, string, etc. In other programming languages, the same data structure is referred to as "associative array" or "hash tables" or "hash maps".
Create a Dictionary
A new dictionary instance is declared using the {} syntax. The dictionary can be empty
d = {}
or it can be populated with values:
d = {'a': 'b', 1: 2, true: "this is true"}
It is good form to insert a space after :.
Access a Dictionary
Access Individual Elements
[], get()
An attempt to access an inexistent key ends up in a KeyError exception being thrown.
Test the existence of a key.
Access:
d["key"]
Get All Keys
Get All Values
Modify a Dictionary
Modify Individual Elements
Add, modify, delete.