# Function like expand.grid in R
**URL:** https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350
**Category:** General Usage
**Tags:** question
**Created:** [June 19, 2017, 5:37pm UTC](https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350 "2017-06-19T17:37:58Z")
**Posts on this page:** 8
**Page:** 2
### Author:  [@piever](https://discourse.julialang.org/u/piever)
#### Post date: [May 28, 2021, 9:34am UTC](https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350/21 "2021-05-28T09:34:45Z")
I think the simplest is to iterate the `Iterators.product`, which gives `Tuple`s (that is, it loses name information). Then you can convert on the fly to named tuples, and pass the resulting iterator to `DataFrame`. For example
```julia
function expand_grid(; kws...)
names, vals = keys(kws), values(kws)
return DataFrame(NamedTuple{names}(t) for t in Iterators.product(vals...))
end
```
---
### Author:  [@DominiqueMakowski](https://discourse.julialang.org/u/DominiqueMakowski)
#### Post date: [July 10, 2023, 1:16pm UTC](https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350/22 "2023-07-10T13:16:19Z")
It would be nice to see this feature added in a “base” package like [StatsModels.jl](https://github.com/JuliaStats/StatsModels.jl) !
---
### Author:  [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)
#### Post date: [July 10, 2023, 6:32pm UTC](https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350/23 "2023-07-10T18:32:45Z")
There a DataFrames.jl function added in the past year called `allcombinations`. See [here](https://dataframes.juliadata.org/stable/lib/functions/#DataAPI.allcombinations)
---
### Author:  [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)
#### Post date: [July 10, 2023, 10:23pm UTC](https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350/24 "2023-07-10T22:23:52Z")
other two ways with and without zip
```julia
julia> a=1:2
1:2
julia> b='a':'c'
'a':1:'c'
julia> c=[1,2,3,4]
4-element Vector{Int64}:
1
2
3
4
julia> r(v,n)= hvncat((ones(Int,n-1)...,size(v)...), true,v...)
r (generic function with 1 method)
julia> DataFrame(NamedTuple.(zip.([[:a,:b,:c]],tuple.(r(a,1),r(b,2),r(c,3))[:])))
24×3 DataFrame
Row │ a b c
│ Int64 Char Int64
─────┼────────────────────
1 │ 1 a 1
2 │ 2 a 1
3 │ 1 b 1
4 │ 2 b 1
⋮ │ ⋮ ⋮ ⋮
22 │ 2 b 4
23 │ 1 c 4
24 │ 2 c 4
17 rows omitted
julia> DataFrame(tuple.(r(a,1),r(b,2),r(c,3))[:])
24×3 DataFrame
Row │ 1 2 3
│ Int64 Char Int64
─────┼────────────────────
1 │ 1 a 1
2 │ 2 a 1
3 │ 1 b 1
4 │ 2 b 1
⋮ │ ⋮ ⋮ ⋮
22 │ 2 b 4
23 │ 1 c 4
24 │ 2 c 4
17 rows omitted
julia> rename(DataFrame(tuple.(r(a,1),r(b,2),r(c,3))[:]),[:a,:b,:c])
24×3 DataFrame
Row │ a b c
│ Int64 Char Int64
─────┼────────────────────
1 │ 1 a 1
2 │ 2 a 1
3 │ 1 b 1
4 │ 2 b 1
⋮ │ ⋮ ⋮ ⋮
22 │ 2 b 4
23 │ 1 c 4
24 │ 2 c 4
17 rows omitted
```
or better this way
```julia
r(v,n)= hvncat(n,v...)
DataFrame(NamedTuple{(:a,:b,:c)}.(tuple.(r.([a,b,c],1:3)...)[:]))
```
---
### Author:  [@Dan](https://discourse.julialang.org/u/Dan)
#### Post date: [July 10, 2023, 11:07pm UTC](https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350/25 "2023-07-10T23:07:49Z")
Another method is using `crossjoin` from DataFrames:
```julia
julia> (Dict(x) for x in pairs((;a = 1:2, b = 'a':'c', c=[1,2,3,4]))) .|>
splat(DataFrame) |> splat(crossjoin)
24×3 DataFrame
Row │ a b c
│ Int64 Char Int64
─────┼────────────────────
1 │ 1 a 1
2 │ 1 a 2
3 │ 1 a 3
4 │ 1 a 4
⋮ │ ⋮ ⋮ ⋮
```
Note the easy no-nonsense syntax specifying `a`,`b`,`c`.
---
### Author:  [@rocco\_sprmnt21](https://discourse.julialang.org/u/rocco_sprmnt21)
#### Post date: [July 11, 2023, 7:25am UTC](https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350/26 "2023-07-11T07:25:41Z")
I reproduce this to show that I understand how your elegant solution works.
```julia
crossjoin(DataFrame.((pairs((;a,b,c))...,))...)
```
Instead I did not understand the meaning of the note (please note that my English is very poor: I use google translator to write)
> [@Dan](#):
>
> Note the easy no-nonsense syntax specifying `a`,`b`,`c`.
---
### Author:  [@gabehassler](https://discourse.julialang.org/u/gabehassler)
#### Post date: [September 22, 2025, 11:20pm UTC](https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350/27 "2025-09-22T23:20:42Z")
The `allcombinations` function in the DataFrames package now does this: [Functions · DataFrames.jl](https://dataframes.juliadata.org/stable/lib/functions/#DataAPI.allcombinations)
```julia-auto
julia> using DataFrames
julia> allcombinations(DataFrame, a = 2:4, b = ['a', 'b'])
6×2 DataFrame
Row │ a b
│ Int64 Char
─────┼─────────────
1 │ 2 a
2 │ 3 a
3 │ 4 a
4 │ 2 b
5 │ 3 b
6 │ 4 b
```
---
### Author:  [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)
#### Post date: [September 23, 2025, 7:56am UTC](https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350/28 "2025-09-23T07:56:57Z")
> [@gabehassler](#):
>
> The `allcombinations` function in the DataFrames package now does this
Apparently, it has been doing that for two years.
See the [post above](https://discourse.julialang.org/t/function-like-expand-grid-in-r/4350/23).
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