Dictionary basics
2. Dictionaries – theory
Dictionaries in loops and conditional statements
Dictionaries in functions


Great! Let's analyze how to create a dictionary in detail.

phonebook = {'Mary': '8349374', 'Anne': '7439834', 'John': '3472983'}

Here, we introduced a dictionary variable with a pair of curly braces { }. Inside, we can provide multiple key-value pairs. Keys are separated from values with a colon (:), and key-value pairs are separated with commas. For instance, in 'Mary':'8349374', 'Mary' is a string key, and '8349374' is a string value.

Keys and values can be of the same type, or their types can differ. For instance:

points = {'John': 83} # string key, integer value
favorite_colors = {'Adam': 'red', 'John': 'blue', 'Jack': 'black'} # string key, string value
annual_weights = {2010: 85.5, 2011: 88.9, 2012: 87.0} # integer key, float value


Create a dictionary of Windows version releases. Store it in a variable named os_releases. The keys should be integers (year of release), and the values should be strings (Windows version names). Put the following items in the dictionary:

  • 2015 – Windows 10
  • 2013 – Windows 8.1
  • 2012 – Windows 8
  • 2009 – Windows 7
  • 2007 – Windows Vista

Stuck? Here's a hint!

Remember to surround the Windows version names with single quotes.