using DataFrames, DataFramesMeta x = ["a", "b", "c", "a", "c", "d"] df = DataFrame(x=x, y = 1:length(x)) z = ["a", "c"] How do I query the items in z in df using DataFramesMeta? @where(df, in(z, :x)) didn’t work. It’s a similar to @where how to select mulit-rows. · Issue #77 · JuliaData/DataFrame…

thanks, can you enlighten me why you used Ref{Array} in the second example? Much appreciated.

The {Array} part is not necessary. Ref(z) would work just as well. The reason we use Ref is because when we broadcast functions across elements of an array, like we are doing above, if one of the arguments, say,x, is broadcastable, like an array, as opposed to a scalar, it tries to apply the functi…

This has come up a bit lately, so I updated an issue comment here . a Scalar function has been discussed before to avoid this confusion.

In Julia 1.0 there’s a curried version of in, meaning that for a vector v in(v) is a function: julia> in([1,2])(1) true julia> in([1,2])(3) false and this can be broadcasted: julia> in([1,2]).(1:3) 3-element BitArray{1}: true true false So I imagine you could do: @where(df, in(z).(:x))

Here is the Query.jl way of doing this: df |> @filter(_.x in z) |> DataFrame

How to select multiple items using DataFramesMeta?

General Usage

kdyrhage October 12, 2018, 1:57pm 2

@where(df, map(c -> c in z, :x))
# or
@where(df, in.(:x, Ref{Array}(z)))

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How to select multiple items using DataFramesMeta?

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