Sorting a Python list by two fields

Question

I have the following list created from a sorted csv

list1 = sorted(csv1, key=operator.itemgetter(1))

I would actually like to sort the list

Answer 1

In ascending order you can use:

sorted_data= sorted(non_sorted_data, key=lambda k: (k[1],k[0]))

or in descending order you can use:

sorted_data= sorted(non_sorted_data, key=lambda k: (k[1],k[0]),reverse=True)

Answer 2

like this:

import operator
list1 = sorted(csv1, key=operator.itemgetter(1, 2))

Answer 3

list1 = sorted(csv1, key=lambda x: (x[1], x[2]) )

Answer 4

Sorting list of dicts using below will sort list in descending order on first column as salary and second column as age

d=[{'salary':123,'age':23},{'salary':123,'age':25}]
d=sorted(d, key=lambda i: (i['salary'], i['age']),reverse=True)

Output: [{'salary': 123, 'age': 25}, {'salary': 123, 'age': 23}]

Answer 5

No need to import anything when using lambda functions.
The following sorts list by the first element, then by the second element.

sorted(list, key=lambda x: (x[0], -x[1]))

Answer 6

employees.sort(key = lambda x:x[1])
employees.sort(key = lambda x:x[0])

We can also use .sort with lambda 2 times because python sort is in place and stable. This will first sort the list according to the second element, x[1]. Then, it will sort the first element, x[0] (highest priority).

employees[0] = Employee's Name
employees[1] = Employee's Salary

This is equivalent to doing the following: employees.sort(key = lambda x:(x[0], x[1]))