Sort an array according other array

General Usage
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1

I am trying to sort an array according other array. More specifically, sort ε_ according Z.

NN = 6
Z = rand(NN)
ε_= rand(NN)
teste = [ Z[sortperm(Z)] ε_[sortperm(ε_)] ]
test_f(Z) = teste[teste[:,1] .== Z , 2]
ε_ = test_f.(Z)

I believe there is a solution in fewer lines.

2

first.(sort(collect(zip(ε_,Z)),by=last))

1 Like
3

You mean?

ε_ .= ε_[sortperm(Z)]

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4

No. It is the same that

ε_[ sortperm(Z) , :]

But my goal is different. You can run my script and will see that it is not the same goal.

5

No. my goal is different. You can run my script and will see that it is not the same goal.

6

Picking easier to read random things, I think this is a less convoluted way to get the same answer:

julia> Z = rand(Int8, 6); println(Z)
Int8[68, -64, -110, 95, -116, 81]

julia> ε_ = rand('a':'z', 6); println(ε_)
['i', 'b', 'u', 'k', 'v', 'j']

julia> teste = [ Z[sortperm(Z)] ε_[sortperm(ε_)] ]
6×2 Matrix{Any}:
 -116  'b'
 -110  'i'
  -64  'j'
   68  'k'
   81  'u'
   95  'v'

julia> test_f(Z) = teste[teste[:,1] .== Z , 2]
test_f (generic function with 1 method)

julia> test_f.(Z)  # desired result?
6-element Vector{Vector{Any}}:
 ['k']
 ['j']
 ['i']
 ['v']
 ['b']
 ['u']

julia> ε_[sortperm(Z)] |> println  # "sort an array according other array"
['v', 'u', 'b', 'i', 'j', 'k']

julia> sort(ε_)[invperm(sortperm(Z))] |> println  # more direct way?
['k', 'j', 'i', 'v', 'b', 'u']
2 Likes
7

Similar result but different output array type, just in case:

test_f2(Z) = teste[indexin(Z,teste[:,1]),2]
test_f2(Z)

6-element Vector{Any}:
 'k': ASCII/Unicode U+006B (category Ll: Letter, lowercase)
 'j': ASCII/Unicode U+006A (category Ll: Letter, lowercase)
 'i': ASCII/Unicode U+0069 (category Ll: Letter, lowercase)
 'v': ASCII/Unicode U+0076 (category Ll: Letter, lowercase)
 'b': ASCII/Unicode U+0062 (category Ll: Letter, lowercase)
 'u': ASCII/Unicode U+0075 (category Ll: Letter, lowercase)
1 Like