Julia: find maximum along columns in array

user_7987200 0
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Suppose we have an array defined like this:

a=[1 2; 3 4; 5 5; 7 9; 1 2];

In Matlab, we could find the maximum values by writing:

 [x y] = max(a)
   x =
     7     9

In Julia, we could use:

  a=[1 2; 3 4; 5 5; 7 9; 1 2]
  findmax(a,1)

returning:

 ([7 9],

  [4 9])

However, I am interested not only in finding [7 9] for the two columns, but also their relative position within each column, like [4, 4]. Of course, I can write a bit more of coding lines, but can I do it directly with findmax?

julia
3 Answers

This is mentioned in the comments but I figured I'd do a response that's easy to see. I have version 1.0.3, so I don't know what's the earliest version that allows this. But now you can just do

julia> findmax(a) #Returns 2D index of overall maximum value
(9, CartesianIndex(4, 2))

julia> findmax(a[:,1]) #Returns 1D index of max value in column 1
(7, 4)

julia> findmax(a[:,2]) #Returns 1D index of max value in column 2
(9, 4)

Hope this makes things easier.

user_97067550
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