How to sort multidimensional array by column?

Question

Is there a way to use the sort() method or any other method to sort a list by column? Lets say I have the list:

[ [John,2], [Jim,9], [Jason,1] ] 

And I wanted to sort it so that it would look like this:

[ [Jason,1], [John,2], [Jim,9], ] 

What would be the best approach to do this?

Edit:

Right now I am running into an index out of range error. I have a 2 dimensional array that is lets say 1000 rows b 3 columns. I want to sort it based on the third column. Is this the right code for that?

sorted_list = sorted(list_not_sorted, key=lambda x:x[2]) 

Answer 1

Yes. The sorted built-in accepts a key argument:

sorted(li,key=lambda x: x[1]) Out[31]: [['Jason', 1], ['John', 2], ['Jim', 9]] 

note that sorted returns a new list. If you want to sort in-place, use the .sort method of your list (which also, conveniently, accepts a key argument).

or alternatively,

from operator import itemgetter sorted(li,key=itemgetter(1)) Out[33]: [['Jason', 1], ['John', 2], ['Jim', 9]] 

Read more on the python wiki.

Answer 2

You can use the sorted method with a key.

sorted(a, key=lambda x : x[1])