Finding the max of a list with multiple elements

Question

I am writing a Python program that produces a list similar to the code block below. The user inputs ten numbers, which are stored in a list. It counts the number of distinct objects. The first number in each ( ) is the number the user entered, and the second value is how many times it was entered. What I need to do is essentially print out to the user "The most common number is x which was entered y times".

organizedList = [(1.0, 5), (5.0, 3)]
print max(organizedList)

I tried a normal max command, but it chooses the second value as the max even thought it was chosen less often. Thank you for your help.

the max function will first look at the first number, returning the max from there. You could simply reverse the order in your array. — quemeraisc, Jun 04 '16 at 19:56
@quemeraisc that would work for this particular input, but is in no way general. — SethMMorton, Jun 04 '16 at 19:56

score 1 · Accepted Answer · answered Jun 04 '16 at 20:00

1

As the other answers have already pointed out, you can tell the max function to only look at the second value by setting the key parameter. To output the result you can do this:

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

print "The most common number is",x,"which was entered",y,"times."

answered Jun 04 '16 at 20:00

Keiwan

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This worked perfectly. Thank you!! – jjj Jun 04 '16 at 20:39

score 0 · Answer 2 · answered Jun 04 '16 at 19:55

0

Use the key option to max, which is a function that tells max what value to base the output on.

organizedList = [(1.0, 5), (5.0, 3)]
print max(organizedList, key=lambda x: x[1])

This will use the 2nd element to determine the maximum value.

answered Jun 04 '16 at 19:55

SethMMorton

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note: You need parenthesis to make this work in python 3: print (…) – ctrl-alt-delor Jun 04 '16 at 19:59
@richard But since the OP was not using parenthesis, we can safely assume they were using Python 2. – SethMMorton Jun 04 '16 at 20:01
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Yes, the note if for Ron, in-case he comes here, looking for an answer. – ctrl-alt-delor Jun 04 '16 at 20:02

score 0 · Answer 3 · answered Jun 04 '16 at 19:55

max has a key argument which you can use to specify on which tuple element the max should be found from.

>>> max(organizedList, key=lambda x: x[1])
(1.0, 5)

Alternatively if you aren't a fan of anonymous functions you could use operator.itemgetter to use the second element similarly with

>>> max(organizedList, key=itemgetter(1))
(1.0, 5)

Querenker · Answer 4 · 2016-06-04T20:07:19.070

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Normaly a list of tuples is sorted by the first element, but you can change the way to get the max element by the key argument

>>> from operator import itemgetter
>>> organizedList = [(1.0, 5), (5.0, 3)]
>>> max(organizedList, key=itemgetter(1))
(1.0, 5)

edited Jun 04 '16 at 20:07

answered Jun 04 '16 at 19:59

Querenker

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Finding the max of a list with multiple elements

4 Answers4