max value of a list filled with named tuples

Question

I create a list filled with named tuples:

from collections import namedtuple
Point = namedtuple('Point', 'x y')
a = Point(5,4)
b = Point(8,3)
tab = [a,b]

print tab
>>[Point(x=5, y=4), Point(x=8, y=3)]

I would like to have the max of the x values in the list 'tab'

max(tab.x)
>> 8

See [this question](http://stackoverflow.com/questions/18296755/python-max-function-using-key-and-lambda-expression) for another approach — Konstantin, Aug 24 '15 at 14:16

Adem Öztaş · Answer 1 · 2015-08-24T14:37:21.280

5

Try like this,

>>> max(tab, key=lambda k: k.x)
Point(x=8, y=3)
>>> max(tab, key=lambda k: k.x).x
8

The optional key argument specifies a one-argument ordering function like that used for list.sort(). The key argument, if supplied, must be in keyword form (for example, max(a,b,c,key=func)).

https://docs.python.org/2/library/functions.html#max

edited Aug 24 '15 at 14:37

answered Aug 24 '15 at 14:16

Adem Öztaş

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Thank you very much. Can you explain me this code please ? : key=lambda k: k.x – Jon Aug 24 '15 at 14:20
`lambda k: k.x` returns sorting key – Adem Öztaş Aug 24 '15 at 14:36
1

Or `key=operator.attrgetter('x')`. – chepner Aug 24 '15 at 14:44

score 2 · Answer 2 · answered Aug 24 '15 at 14:09

2

You may simple do it as :

print max([i.x for i in tab])

However it may not be the best approach to do the same.

answered Aug 24 '15 at 14:09

ZdaR

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max value of a list filled with named tuples

2 Answers2