How to convert a nested array to a multidimensional array in Julia

Question

I want to make Array{UInt8,3} (color image data) from Array{UInt8,2} (grayscale image data) in Julia 0.4 like the following:

using Images
dat = data(img)
dat2 = map(x -> (v = x*2 % UInt8; [v,0,0]), dat)
img2 = colorim(dat2)

However, the code above makes Array{Array{UInt8,1},2} instead. How can I make a "flatten" multidimensional array?

tholy · Accepted Answer · 2015-10-26 11:40:42Z

4

You can also use

z = zeros(UInt8, size(A))
colorim(cat(3, A, z, z))

where A is whatever you want in the red channel.

answered Oct 26, 2015 at 11:40

tholy

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Comments

Dan Getz · Accepted Answer · 2015-10-24 10:10:01Z

2

Using array comprehension:

dat2 = UInt8[k==1 ? (dat[i,j]*2)%UInt8 : zero(UInt8)
             for i=1:size(dat,1),j=1:size(dat,2),k=1:3]

answered Oct 24, 2015 at 10:10

Dan Getz

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Reza Afzalan · Accepted Answer · 2015-10-24 17:26:16Z

2

Another approach could be:

dat2=zeros(UInt8,(size(dat)...,3))
dat2[:,:,1]=2*dat1

answered Oct 24, 2015 at 17:26

Reza Afzalan

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