CODEWITHSUNDEEP
pythonlist
Ssank
Ssank

Reputation: 3677

comparing two lists to choose maximum

I have two lists l1 and l2:

l1 = [x,y,3,4,5]
l2 = [x,y,30,1,2]

I want to make a list l3 which is the list that has the maximum in the 3rd element of the list (in the above example it would be 3 in l1 and 30 in l2). In the above case l3 = [x,y,30,1,2] How can I do this?

Upvotes: 1

Views: 478

Answers (2)

Padraic Cunningham
Padraic Cunningham

Reputation: 180540

You can use a simple if/else considering you are just comparing two elements:

l3 = l1 if l1[2] > l2[2] else l2

But beware you are creating a reference not a copy.

If you want a new list you need to copy:

l3 = l1[:] if l1[2] > l2[2] else l2[:]

If you don't copy any changes to in this case l2 as it has the larger third element will be reflected in l3 and vice-versa.

Also if you have other mutable objects in the list you will need to make a copy.deepcopy:

from copy import deepcopy
l3 = deepcopy(l1 ) if l1[2] > l2[2] else deepcopy(l2)

Upvotes: 1

Cory Kramer
Cory Kramer

Reputation: 118021

You can use the key argument of max to get the list with the larger element [2]

l3 = max((l1, l2), key = lambda i: i[2])

Upvotes: 4

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