Ways to sort list of dictionaries by values in Python – Using lambda function
Sorting has always been a useful utility in day-to-day programming. Dictionary in Python is widely used in many applications ranging from competitive domain to developer domain(e.g. handling JSON data). Having a knowledge to sort dictionaries according to its values can prove useful in such cases.
There are 2 ways to achieve this sorting, namely by
- Using lambda functions
- Using itemgetter
This article deals with sorting using lambda function and using “sorted()” inbuilt function. Various variations can also be achieved for sorting the dictionaries.
- For descending order : Use “reverse = True” in addition to the sorted() function.
- For sorting w.r.t multiple values : Seperate by “comma” mentioning the correct order in which sorting has to be performed.
# Python code demonstrate the working of # sorted() with lambda # Initializing list of dictionaries lis = [{ "name" : "Nandini", "age" : 20}, { "name" : "Manjeet", "age" : 20 }, { "name" : "Nikhil" , "age" : 19 }] # using sorted and lambda to print list sorted # by age print "The list printed sorting by age: "print sorted(lis, key = lambda i: i['age']) print ("\r") # using sorted and lambda to print list sorted # by both age and name. Notice that "Manjeet" # now comes before "Nandini" print "The list printed sorting by age and name: "print sorted(lis, key = lambda i: (i['age'], i['name'])) print ("\r") # using sorted and lambda to print list sorted # by age in descending order print "The list printed sorting by age in descending order: "print sorted(lis, key = lambda i: i['age'],reverse=True) |
Output:
The list printed sorting by age:
[{'age': 19, 'name': 'Nikhil'}, {'age': 20, 'name': 'Nandini'}, {'age': 20, 'name': 'Manjeet'}]
The list printed sorting by age and name:
[{'age': 19, 'name': 'Nikhil'}, {'age': 20, 'name': 'Manjeet'}, {'age': 20, 'name': 'Nandini'}]
The list printed sorting by age in descending order:
[{'age': 20, 'name': 'Nandini'}, {'age': 20, 'name': 'Manjeet'}, {'age': 19, 'name': 'Nikhil'}]