julia find in matrix with (row,col) instead of index -



julia find in matrix with (row,col) instead of index -

in julia can find coordinates of elements in matrix via:

julia> find( x -> x == 2, [ 1 2 3; 2 3 4; 1 0 2] ) 3-element array{int64,1}: 2 4 9

these values right prefer (row,col) tuples instead.

(1,2) (2,1) (3,3)

what easiest way accomplish in julia?

i don't believe there inbuilt way it, here function it

function findmat(f, a::abstractmatrix) m,n = size(a) out = (int,int)[] in 1:m, j in 1:n f(a[i,j]) && push!(out,(i,j)) end out end

e.g.

julia> findmat(x->x==2, [ 1 2 3; 2 3 4; 1 0 2] ) 3-element array{(int64,int64),1}: (1,2) (2,1) (3,3)

if big number of items satisfy status might more efficient in 2 passes, uncertainty it.

matrix find julia-lang

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