Day 69: Python has a big dictionary
Python Dictionary
We’ll take another practical look at it today.
Definition
A dictionary is a data store that stores data in key-value pairs.
A dictionary is ordered(as of python 3.7, earlier versions are unordered)
Creating a dictionary
print ('0. Dictionaries are created using curly braces and are of class dict')
my_dict = {}
print (type(my_dict))
Result
0. Dictionaries are created using curly braces and are of type dict
<class 'dict'>
A dictionary is created by using curly braces,
Here we are creating an empty dictionary.
Adding data
print ('1. Dictionaries are created by using key-value pairs, separated by commas')
my_dict = {'name' : 'Barry', 'hero' : 'flash', 'speciality' : 'speed'}
print (my_dict)
Result
1. Dictionaries are created by using key-value pairs, separated by commas
{'name': 'Barry', 'hero': 'flash', 'speciality': 'speed'}
Adding more data?
print ('2. Would this work?')
my_dict['name'] = 'Clark'
my_dict['hero'] = 'Superman'
my_dict['speciality'] = ' strength'
print(my_dict)
No !
Rethinking this
It’s important to understand that dictionaries are made up of key value pairs.
And you can add as much data as you require.
The important thing is to figure out what piece of data should be the key.
print ('3. Rethinking the key first')
my_dict = {}
my_dict['Barry'] = {'fullname' : 'Barry Allen', 'hero' : 'The Flash', 'speciality' : 'Speed'}
print (my_dict)
Really adding more data
my_dict = {}
my_dict['Barry'] = {'fullname' : 'Barry Allen', 'hero' : 'The Flash', 'speciality' : 'Speed'}
print (my_dict)
print ('4. Adding more data')
my_dict['Clark'] = {'fullname': 'Clark Kent', 'hero' : 'Superman', 'speciality' : 'Strength'}
print (my_dict)
Getting the values from keys
print (my_dict['Barry'])
#OUTPUT--> {'fullname': 'Barry Allen', 'hero': 'The Flash', 'speciality': 'Speed'}
print (my_dict['Barry']['fullname'])
#OUTPUT--> Barry Allen
print (my_dict['Barry']['hero'])
#OUTPUT--> The Flash
Conclusion
Dictionaries can be used to store a very large amount of temporary data.
Ideal for cases where we need some data put away and we only need it for immediate processing and we don’t necessarily need to keep it to file.
Once you figure out the key that you want, the values and other sub-keys can be many !