Python 3 Tutorial for Beginners #08 – Python 3 Dictionary Basics

Python 3 dictionary is a versatile and easy to use hash-map implementation. It is simply a built-in data type that you can hack upon.

How to Create a Python 3 Dictionary

There are multiple ways you can create a dictionary. However, simplest form is using a literal.

d = {'apple': 5, 'orange': 2}

If you want to create an empty dictionary, this is how you do it:

d = {} # Creates an empty dict

When Should I use a Dictionary?

Are you looking to map a value to some other value? Then the dictionary is what you are looking for.

Note: Keys must be immutable and hashable. This means that you can use int, str, tuple, or frozenset as a key but not lists.

Python 3 Dictionary Literal Syntax

Dictionaries are made of key:value pairs. You can specify one or more pairs in the dictionary literal form. Also, commas are used to separate different key:value pairs in the dictionary.

Python 3 Dictionary Syntax Explained
Python 3 Dictionary Syntax Explained

Set and Delete Items from a Dict

Let’s take the above defined dictionary and add a new element to it. If the ‘banana’ is already present in the dictionary this will overwrite it.

d['banana'] = 4

Also, you can delete information about ‘apple’

del d['apple']

Note: You will get a KeyError exception if the given key is not present when deleting.

How to Check If a Python 3 Dictionary Has a given Key

Checking the availability of a key is very simple in Python.

if 'banana' in d:
    print('No bananas')

Also, you can check if a key is not in a dictionary

if 'apple' not in d:
    print("Oh, I deleted apples")

How to Count Number of Characters in a Phrase

Python 3 Dictionary Character Counter
Python 3 Dictionary Character Counter

That’s it for this tutorial. Next tutorial will also be about dictionaries. Please comment below if you have any questions. See Python 3 Dictionary Usage for the next awesome dictionary tutorial.

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