CODEWITHSUNDEEP
selectmatrixjulia
Sibylse
Sibylse

Reputation: 187

Selecting columns/rows of a matrix in Julia

this is a very basic problem but I didn't find any hints on it. Let's say I have a 2x4 matrix and I want to reduce the dimension of the matrix to only these columns that are in the sum larger than 1:

A=rand(2,4)
ind = sum(A,1).>1

That gives me an indicator of the columns I want to retain. Naively one would assume that I can do that:

A[:,ind]

which doesn't work as ind is a BitArray and only for Bool Arrays this is allowed, i.e., the following works

A[:,[true,true,false,true]]

in return, the following does work:

A[A.>0.5]

But it returns a vector of filtered elements. What is the logic behind this and how do I solve my problem?

Upvotes: 5

Views: 10145

Answers (1)

Chris Rackauckas
Chris Rackauckas

Reputation: 19162

As noted in the comments, this is fixed by using a version of Julia which is >=v0.4.

Upvotes: 1

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