What is Julia's equivalent of R's %in%

[Luigi_Marongiu]

hello,
I have two different dataframes with different columns and headers, but the columns Start and Start_site are related and in particular I want to select the rows of the first dataframe with Start matching the second dataframe with Start_site.
Essentially I am looking for the julia equivalent of R’s Start %in% Start_site.
I tried with join, but it requires the same dataframe structure…
Thanks

[Luigi_Marongiu]

Nevermind, I found it:

join(df1, df2; on = :Start, kind = :semi, makeunique = false,
                   indicator = nothing, validate = (false, false))

I had to call the columns with the same name

[ElOceanografo]

There is also the in function:

start = [1, 3, 4, 6]
start_site = 1:5 
in_start_site = in(start_site) # in(...) returns a function
in_start_site.(start) #  [true, true, true, false]

in(collection) returns a function that tests if something is in collection. You can also write this in one line:

in(start).(start_site)

[Tamas_Papp]

cf

Julia's in.() seems slow compared to R's %in%

Hi everyone, I want to compare if elements of vector x are in elements of vector y. In R, I can do this as follows: > x <- c("a", "b", "c") > y <- c("b", "a") > x %in% y [1] TRUE TRUE FALSE In Julia, I can do this as follows: julia> x = ["a", "b", "c"]; julia> y = ["b", "c"]; julia> in.(x, Ref(y)) 3-element BitArray{1}: false true true Now let’s make the vector big: In R, > set.seed(123) > x <- rnorm(100000, 1000, 2) > y <- rnorm(100000, 1000, 2) > system.time(x %in% y) user sy…

TL;DR: you are probably looking for

x .∈ Ref(Set(y))

[Luigi_Marongiu]

Hello, I got a slight variation of this problem. Instead of testing arrays, I would like to select the rows of a dataframe whose column X corresponds to the all the elements of an array. In other words:
if I have an array x=["a", "b", "c"] and a dataframe df with unique(df[:X]) = "a", "c", "d", "g", can I make a selection? df[df[:X] .== x, :], df[df[:X] .∈ x, :] and df[occursin.(x, df.X), :] did not work…

[nilshg]

df[in(x).(df.X), :]

[Luigi_Marongiu]

what would be the negation of this? that is how to select the rows of the dataframe whose field X IS NOT in x?

[MrUrq]

julia> x=["a","b","c"]
julia> df = DataFrame(X = ["a","c","d","g"])

julia> df[.!in(x).(df.X),:]

2×1 DataFrame
│ Row │ X      │
│     │ String │
├─────┼────────┤
│ 1   │ d      │
│ 2   │ g      │

[Mattriks]

or:

join(df1, df2, on=:X, kind=:anti)

?join

[pdeffebach]

filter(df) do row
    row.X in x
end