# Map over combinations of parameters, and grouping results as DataFrame

**URL:** <https://discourse.julialang.org/t/map-over-combinations-of-parameters-and-grouping-results-as-dataframe/77306>\
**Category:** General Usage\
**Tags:** dataframes\
**Created:** [March 2, 2022, 2:27pm UTC](https://discourse.julialang.org/t/map-over-combinations-of-parameters-and-grouping-results-as-dataframe/77306 "2022-03-02T14:27:25Z")\
**Posts on this page:** 1\
**Showing post:** 10

<div class="post-metadata">

**Author:** ![baptnz](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/baptnz/32/24519_2.png) [@baptnz](https://discourse.julialang.org/u/baptnz)\
**Post date:** [March 3, 2022, 10:34am UTC](https://discourse.julialang.org/t/map-over-combinations-of-parameters-and-grouping-results-as-dataframe/77306/10 "2022-03-03T10:34:15Z")

</div>

I’ve noticed that `reduce` has an optional `source` argument specifically to keep track of each block. With this, I now have the following wrapper:

```julia

function expand_grid(; kws...)
    names, vals = keys(kws), values(kws)
    return DataFrame(NamedTuple{names}(t) for t in Iterators.product(vals...))
end

function mymodel(;x = range(0, 10, length = 100), a = 1, b = 1, c = 2, fun = sin, kws...)
    DataFrame(x = x, y = a .* sin.(b .* x) .+ c, z = a .* fun.(b .* x) .+ c)
end

function pmap_df(p, f, kws...; join=true)
   tmp = map(f, eachrow(p), kws...)
   all = reduce(vcat, tmp, source="id")
   if !join
    return all
   end
   p[!, :id] = 1:nrow(p)
   return DataFrames.leftjoin(p, all, on=:id)
end

params = expand_grid(a=[0.1,0.2,0.3], b = [1,2,3], c = [0,0.5]);

pmap_df(params, p -> mymodel(;p..., fun=tanh))

```

That’s pretty close to what I was after; I’d still like to merge the map+reduce steps with `mapreduce`, but I’m not sure how to pass extra arguments to `reduce`. Any idea?

---

_[View the full topic](https://discourse.julialang.org/t/map-over-combinations-of-parameters-and-grouping-results-as-dataframe/77306)._