# Julia 1.7 sort issue?
**URL:** https://discourse.julialang.org/t/julia-1-7-sort-issue/117531
**Category:** General Usage
**Created:** [July 26, 2024, 8:55pm UTC](https://discourse.julialang.org/t/julia-1-7-sort-issue/117531 "2024-07-26T20:55:10Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@danny.s](https://discourse.julialang.org/u/danny.s)
#### Post date: [July 26, 2024, 8:55pm UTC](https://discourse.julialang.org/t/julia-1-7-sort-issue/117531/1 "2024-07-26T20:55:11Z")
I was trying to do some lexicographic sorting and came up with this “simple” code (sorry for the kinda long matrix, everything seems to work fine for the full slice):
```julia
final_pts = [0.5 0.1127016653792583 0.6116933432144834 0.5 0.5 0.9442296164361286 0.1127016653792583 0.5 0.5 0.8872983346207417 0.9802456343540101 0.5 0.5 0.5 0.18944852663138678 0.7171218746734013 0.9969159816063775 0.0030840183936224896 0.1127016653792583 0.38830665678551657 0.5 0.5 0.5 0.055770383563871484 0.01975436564598987 0.5 0.28287812532659873 0.5 0.5 0.8105514733686132 0.5 0.8872983346207417 0.8872983346207417; 0.9969159816063775 0.5 0.5 0.8105514733686132 0.28287812532659873 0.5 0.1127016653792583 0.9802456343540101 0.5 0.8872983346207417 0.5 0.9442296164361286 0.6116933432144834 0.1127016653792583 0.5 0.5 0.5 0.5 0.8872983346207417 0.5 0.0030840183936224896 0.7171218746734013 0.18944852663138678 0.5 0.5 0.8872983346207417 0.5 0.01975436564598987 0.055770383563871484 0.5 0.38830665678551657 0.5 0.1127016653792583]
function lt_slice(mat)
function comp(i, j)
ret = any(mat[k, i] < mat[k, j] for k in axes(mat, 1))
@info "" i j size(mat) ret
ret
end
comp
end
sort(collect(1:size(final_pts, 2)), lt=lt_slice(final_pts))
```
This gives an out-of-bounds exception in 1.7, an example shown below:
```julia
ERROR: BoundsError: attempt to access 2×33 Matrix{Float64} at index [1, 34]
Stacktrace:
[1] getindex
@ ./array.jl:862 [inlined]
[2] #10
@ ./none:0 [inlined]
[3] iterate
@ ./generator.jl:47 [inlined]
[4] _any
@ ./reduce.jl:1109 [inlined]
[5] any
@ ./reduce.jl:1105 [inlined]
[6] any
@ ./reduce.jl:1031 [inlined]
[7] (::var"#comp#11"{Matrix{Float64}})(i::Int64, j::Int64)
@ Main ./REPL[94]:3
[8] #1
@ ./ordering.jl:125 [inlined]
[9] lt
@ ./ordering.jl:112 [inlined]
[10] partition!(v::Vector{Int64}, lo::Int64, hi::Int64, o::Base.Order.Lt{Base.Order.var"#1#3"{var"#comp#11"{Matrix{Float64}}, typeof(identity)}})
@ Base.Sort ./sort.jl:559
[11] sort!(v::Vector{Int64}, lo::Int64, hi::Int64, a::Base.Sort.QuickSortAlg, o::Base.Order.Lt{Base.Order.var"#1#3"{var"#comp#11"{Matrix{Float64}}, typeof(identity)}})
@ Base.Sort ./sort.jl:575
[12] sort!
@ ./sort.jl:664 [inlined]
[13] #sort!#8
@ ./sort.jl:725 [inlined]
[14] #sort#9
@ ./sort.jl:772 [inlined]
[15] top-level scope
@ REPL[104]:1
```
I’ve tried it on three different machines and this behavior doesn’t happen in 1.10, but only 1.7 (and with different invalid indices). I added the `@info` to ensure that it’s shown my comparison doesn’t access the wrong index and it’s instead a problem with `sort!`.
1. Does someone else get this behavior?
2. Is it a problem with my code?
3. If not, is this already known? I did a preliminary search and didn’t see anything
4. If not, is it worth opening an issue on Julia’s github, since it’s a previous version?
---
### Author:  [@stillyslalom](https://discourse.julialang.org/u/stillyslalom)
#### Post date: [July 26, 2024, 9:31pm UTC](https://discourse.julialang.org/t/julia-1-7-sort-issue/117531/2 "2024-07-26T21:31:45Z")
Putting aside the error, does `sortslices` work for you? The default comparison is lexicographic.
```julia
julia> sortslices(final_pts, dims=2)
2×33 Matrix{Float64}:
0.00308402 0.0197544 0.0557704 0.112702 0.112702 0.112702 … 0.887298 0.887298 0.94423 0.980246 0.996916
0.5 0.5 0.5 0.112702 0.5 0.887298 0.5 0.887298 0.5 0.5 0.5
```
---
### Author:  [@danny.s](https://discourse.julialang.org/u/danny.s)
#### Post date: [July 26, 2024, 9:43pm UTC](https://discourse.julialang.org/t/julia-1-7-sort-issue/117531/3 "2024-07-26T21:43:52Z")
Unfortunately, not; I need the permutation to sort both the matrix and an associated vector with length `size(final_pts,2)` (otherwise, sortslices would be great!).
---
### Author:  [@nilshg](https://discourse.julialang.org/u/nilshg)
#### Post date: [July 26, 2024, 9:44pm UTC](https://discourse.julialang.org/t/julia-1-7-sort-issue/117531/4 "2024-07-26T21:44:06Z")
> [@danny.s](#):
>
> If not, is it worth opening an issue on Julia’s github, since it’s a previous version?
Probably no - 1.10 will be the LTS version very shortly, and 1.7 was never an LTS version anyway, so there won’t be a 1.7.4 release that would fix this issue if it really is one.
---
### Author:  [@danny.s](https://discourse.julialang.org/u/danny.s)
#### Post date: [July 26, 2024, 9:51pm UTC](https://discourse.julialang.org/t/julia-1-7-sort-issue/117531/5 "2024-07-26T21:51:27Z")
I guess I should’ve tested it on other versions, but I assume this got fixed when they changed the base sorting algorithm in 1.9, because I just checked and it doesn’t work using the default algorithms in 1.6, 1.7, 1.8, but works in 1.9, 1.10.
On the other hand, if I use `alg=Base.InsertionSort` in `<1.9`, it works. If I use `alg=Base.QuickSort` in `>=1.9`, it no longer works, so I think that this is a quicksort issue in previous non-LTS versions?
~~Given this research, I’ll probably open an issue since it’s no longer just an older non-LTS version.~~
EDIT: Adding that a simple thought process leads me to realize this is a problem with unstable lexicographic sorting. As suggested [here](https://github.com/JuliaLang/julia/issues/9258#issuecomment-1183294739), in `>1.9` you can do `sortperm(eachcol(matrix))` and before that you can just do `sortperm(collect(eachcol(matrix)))`
---
### Author:  [@mkitti](https://discourse.julialang.org/u/mkitti)
#### Post date: [July 28, 2024, 12:03am UTC](https://discourse.julialang.org/t/julia-1-7-sort-issue/117531/6 "2024-07-28T00:03:02Z")
Technically this is a bug in Julia 1.6 LTS as well, which is still LTS until Julia 1.11 is actually released.