What is a dictionary in Python?
Creating a dictionary
A dictionary is pretty much how it sounds, it contains a term and then a definition, and uses curlybrackets:
myDict = { "Name" : "John", "Role" : "Analyst", "Age" : 22, "Single" : False } print myDict
Outputs: { "Age" : 22, "Role" : "Analyst", "Single" : False, "Name" : "John" }
Notice that like other lists, a dictionary can contain multiple value types, strings, integersand Booleans.
Like sets, dict’s:
- Cannot have the same key multiple times (a dict wouldn’t contain 2 “Name” entries)
- Have no specific order when printed
Selecting an item from a Dictionary
To select an item, we would use the Key rather than a number, lets use the example above:
myDict = { "Name" : "John", "Role" : "Analyst", "Age" : 22, "Single" : False } print myDict['Name']
Outputs: John
As you can see, we have returned the value associated with the “Name” key.
Reassigning Values
You can reassign values in dictionary’s:
myDict['Name'] = 'Steve' print myDict
Outputs: { "Age" : 22, "Role" : "Analyst", "Single" : False, "Name" : "Steve" }