CODEWITHSUNDEEP
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mackbox
mackbox

Reputation: 199

How to pass each element in a list as arguments of another function in R?

Suppose I got a list (in my situation the number of elements in the list is variable), 

    tmp=c('X1','X2','X3','X4')

I'd like to pass each element to the expand grid function like this:

    tmp1=expand.grid(X1=c(0,1),X2=c(0,1),X3=c(0,1),X4=c(0,1))

where each element can just take values 0 and 1. How could I achieve this?

Thanks.

Upvotes: 0

Views: 194

Answers (1)

akrun
akrun

Reputation: 886938

We can use mget to get the values of the elements in the 'tmp' vector as a list and then wrap it with expand.grid.

expand.grid(mget(tmp))

Or if these are not objects, but the column names we need to create with expand.grid, then place the vector c(0,1) in a list, replicate it by the length of 'tmp', do the expand.grid and set the column names as 'tmp' (with setNames)

setNames(expand.grid(rep(list(0:1), length(tmp))), tmp)
#    X1 X2 X3 X4
#1   0  0  0  0
#2   1  0  0  0
#3   0  1  0  0
#4   1  1  0  0
#5   0  0  1  0
#6   1  0  1  0
#7   0  1  1  0
#8   1  1  1  0
#9   0  0  0  1
#10  1  0  0  1
#11  0  1  0  1
#12  1  1  0  1
#13  0  0  1  1
#14  1  0  1  1
#15  0  1  1  1
#16  1  1  1  1

Upvotes: 1

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