# Slicing and merging of CartesianIndices

**URL:** <https://discourse.julialang.org/t/slicing-and-merging-of-cartesianindices/61519>\
**Category:** General Usage\
**Tags:** indexing\
**Created:** [May 20, 2021, 1:55pm UTC](https://discourse.julialang.org/t/slicing-and-merging-of-cartesianindices/61519 "2021-05-20T13:55:11Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![sijo](https://avatars.discourse-cdn.com/v4/letter/s/da6949/32.png) [@sijo](https://discourse.julialang.org/u/sijo)\
**Post date:** [May 20, 2021, 4:15pm UTC](https://discourse.julialang.org/t/slicing-and-merging-of-cartesianindices/61519/2 "2021-05-20T16:15:14Z")

</div>

You can do use `ci.indices` though I think that’s an undocumented internal:

```julia
ci1 = CartesianIndices(ci.indices[1])
ci2 = CartesianIndices(ci.indices[2])

```

You can get the same information with `first(ci)`, `step(ci)`, `last(ci)` but that’s less convenient.

To recover the full list:

```julia
CartesianIndices((ci1.indices[1], ci2.indices[1]))

```

Another idea using arrays of `CartesianIndex` rather than `CartesianIndices`:

```julia
julia> i1 = getindex.(ci[:, 1], 1)
3-element Vector{Int64}:
 2
 4
 6

julia> i2 = getindex.(ci[1, :], 2)
3-element Vector{Int64}:
 3
 6
 9

julia> CartesianIndex.(i1, i2')
3×3 Matrix{CartesianIndex{2}}:
 CartesianIndex(2, 3) CartesianIndex(2, 6) CartesianIndex(2, 9)
 CartesianIndex(4, 3) CartesianIndex(4, 6) CartesianIndex(4, 9)
 CartesianIndex(6, 3) CartesianIndex(6, 6) CartesianIndex(6, 9)

```

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