DataFrames specialization and latency

select_subset_test.jl

using DataFrames, SnoopCompile, Statistics, ProfileView
# Note: load all packages first to prevent invalidation

d = DataFrame(n = 1:20, x = [3, 3, 3, 3, 1, 1, 1, 2, 1, 1,
                             2, 1, 1, 2, 2, 2, 3, 1, 1, 2]);
g = groupby(d, :x);

subset(g,  :n => (n -> n .> mean(n))); # compile
select(g,  :n => (n -> n .> mean(n))); # compile

tinf_subset = @snoopi_deep begin
    subset(g,  :n => (n -> n .> mean(n)))
end
tinf_select = @snoopi_deep begin
    select(g,  :n => (n -> n .> mean(n)))
end