Article Outline
In <a href="https://python.org">Python</a> a dictionary is a <a href="https://pythonbasics.org/dictionary/">key-value mapping</a>. Its a set of key-value pairs, every key has a value.
You can use this to <a href="https://pythonspot.com/python-dictionaries/">receive values using keys</a>. Values in a dictionary can be of any data type. The data in a dictionary is not in any specific order.
This means you can define a dict with key-value pairs like this:
>>> di = { 'five': 5, 'two': 2, 'one': 1 }
>>> di
{'five': 5, 'two': 2, 'one': 1}
>>> You can call the list method with the dictionary as parameter. This outputs all the keys:
>>> list(di)
['five', 'two', 'one']Sort dictionary by values
Each pair in a dictionary is a key-value pair. For the dictionary above 'five','two' and 'one' are keys. The values are 1,2,5 and each are mapped.
To sort a dictionary by values you can use:
>>> sorted(di.values())
[1, 2, 5]Sort dict by keys
You can sort by keys too:
>>> sorted(di)
['five', 'one', 'two']This is in alphabetic order, 'f' before 'o' and 't'.
Real world example
You can define a dictionary with months like this:
>>> month = { 'January':1, 'February':2, 'March':3, 'April':4, 'May':5, 'June':6 }Then you can sort by keys or values:
>>> sorted(month)
['April', 'February', 'January', 'June', 'March', 'May']
>>> sorted(month.values())
[1, 2, 3, 4, 5, 6]
You can sort in reverse order too:
>>> sorted(month, reverse=True)
['May', 'March', 'June', 'January', 'February', 'April']Related links:
- <a href="https://pythonbasics.org/dictionary/">Python dictionary</a>
- <a href="https://wiki.python.org/moin/HowTo/Sorting">More on sorting in Python</a>
- <a href="https://pythonbasics.org">Learn Python</a>