CODEWITHSUNDEEP
r
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Reputation: 180

Expand dataframe but retain variables in R

I would like to expand a dataframe based on all pairwise combinations of one variable while keeping the associate value of a second variable. For example: 

V1 <- letters[1:2]
V2 <- 1:2
df <- data.frame(V1, V2)

I would like to return:

Var1 Var2 Var3 Var4
a    a    1    1
b    a    2    1
a    b    1    2
b    b    2    2

I can use expand.grid(df$V1, df$V1) to get all of the pairs, but I'm not sure how to include the second variable without having its values expanded also.

Upvotes: 1

Views: 206

Answers (1)

akrun
akrun

Reputation: 886938

If we need to expand each column separately, then we can do this with Map where the arguments are two 'df' objects

do.call(cbind, Map(expand.grid, df, df))

Upvotes: 1

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