Solve a Debate

[nexes]

Alright so me and my friend are having argument.

Ok the problem we had been asked a while back, to do a programming
exercise (in college)
That would tell you how many days there are in a month given a
specific month.

Ok I did my like this (just pseudo):

If month = 1 or 3 or etc ....
        noDays = 31
Elseif month = 4 or 6 etc ....
        noDays = 30
Else
        noDays = 29
(we didn't have to take into account a leap year)

He declared an array and assigned the number of days in a month to its
own element in an array. Now
I realise that in this example it would not make a difference in terms
of efficiency, but it is my belief that if
there is more data that needed to be assigned(i.e. a couple megs of
data) it would be simpler (and more efficient) to
do a compare rather then assigning all that data to an array, since
you are only going to be using 1 value and the rest
of the data in the array is useless.

What are everyone else's thoughts on this?