Slice Arrays of Arrays

New to Julia
1

I have an array of arrays:
a=Array[[1,2,3,4],[11,12,13,14],[21,22,23,24]]

How can I get second and third element of each array?
[[2,3],[12,13],[22,23]]

I have tried it but it does not work:
a[:,2:3]

2

getindex.(a,2) gets the second element of each array
You can also do reduce(hcat, a)[2:3,:], but that copies all the data into a matrix before extracting the relevant rows

2 Likes
3

Here are two ways to do this:

reduce(hcat, getindex.(a, Ref(2:3)) )
getindex.(a, (2:3)')

Ref(2:3) means that this behaves like a scalar as far as broadcasting is concerned. Transposing it instead means that the 2nd axis of the result comes from 2:3, and the first from a.

3 Likes
4

This one is a keeper! :slight_smile:

1 Like
5

Thanks to your help, I have solved my problem.
Regards,