finding maximum value in python list of tuples

Question

I have a list of tuples (list):

('2015-06-19', 3453455, 5, 'Scheduled')
('2015-05-19', 6786788, 6, 'Overdue')
('2015-04-19', 2342344, 2, 'Not Received')
('2015-03-19', 9438549, 0, 'Not Received')
('2015-02-19', 6348759, 7, 'Not Received')

When I run this, I get this:

>>> print(max(list))
('2015-06-19', 3453455, 5, 'Scheduled')

Obviously, max(list) determined the max based on the first value in the list of tuples. I'm just wondering if this is the default behavior of max(list) in regards to a list of tuples; to check only the first item in the tuple?

And, what if I wanted to return the tuple with the maximum based on the second item/column. How would I do that?

See this: http://stackoverflow.com/questions/5292303/python-tuple-comparison — aldeb, May 29 '15 at 16:19
it would check the subsequent values if the first value of any tuple matches. — ZdaR, May 29 '15 at 16:19
You can change this behavior if you like: `max(tup_list, key= lambda x: x[1])` — kylieCatt, May 29 '15 at 16:20

nomis · Answer 1 · 2015-05-29T16:23:51.770

16

You can specify which field to use for comparison using lambdas

max(list,key=lambda x:x[1])

or alternatively, using itemgetter

from operator import itemgetter
max(list,key=itemgetter(1))

edited May 29 '15 at 16:23

answered May 29 '15 at 16:20

nomis

2,545
1
14
15

great answer, i always prefer `itemgetter` which is faster – jamylak May 29 '15 at 16:40

finding maximum value in python list of tuples

1 Answers1

Linked