CODEWITHSUNDEEP
pythonlistsorting
Oren
Oren

Reputation: 5309

sort a 2D list first by 1st column and then by 2nd column

I am trying to find a nice way to sort a 2d list , first by the 1st value , and then by the 2nd value.

I think an example will be the best If I have a list

[[1,4],
[2,7],
[10,1],
[1,2],
[10,6]
[2,1]]

I want that is will be sorted like this

[[1,2],
[1,4],
[2,1],
[2,7],
[10,1],
[10,6]]

Upvotes: 21

Views: 38177

Answers (1)

Padraic Cunningham
Padraic Cunningham

Reputation: 180401

l=[[1,4],
[2,7],
[10,1],
[1,2],
[10,6],
[2,1]]
print(sorted(l,key=lambda x: (x[0],x[1]))) # use lambda to sort by "x[0]"-> first element of the sublists or x[1] -> second element, if its a tie
[[1, 2], [1, 4], [2, 1], [2, 7], [10, 1], [10, 6]]

Or simply sorted(l) of l.sort() as your elements sort naturally.

A better example would be to sort by the second value only:

print(sorted(l,key=lambda x: (x[1])))
[[10, 1], [2, 1], [1, 2], [1, 4], [10, 6], [2, 7]]

Upvotes: 42

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