Dictionary in Python

Video Transcription

Hi, my name is Art and I teach Python at Noble Desktop. In this video, I'll explain dictionaries to you. Remember that Python has built-in data types like integers, floats, strings, and lists. How do you initialize a dictionary?

First, come up with a variable name, like 'd', and use curly braces. To check if it's a dictionary, use the 'type' function and it should return 'dictionary'.

Before I give you a formal definition of a dictionary, let me show you how we can populate the dictionary with data. Suppose this is my phone book, and I have a friend named John. John is the key, and 'Manhattan' is the value. We can add another friend, Mary, her phone number, and also Mark and his phone number.

A dictionary is a completely different collection than what we've seen so far - it is a collection of items, where each item has a key and a value, separated by a colon and each item separated by a comma. Keys must be unique.

It's easy to update values - just use the key and assign a new value. To see all keys, use the 'keys' function. To fetch a value, use the key in square brackets. To update a value, use the key in square brackets and assign a new value.

Watch my other videos to learn how to use a 'for' loop to iterate through a dictionary.