Is there ONE function in R which gives out a similar output to MATLAB's ismember() if I want a logical array and the indexes of locations where the array elements are members of set array.
Matlab code:
A = [5 3 4 2]; B = [2 4 4 4 6 8]; [la loc] = ismember(A,B) Output:
la = 1x4 logical array 0 0 1 1 loc = 0 0 2 1 To get a similar output in R right now I use this:
ismember <- function(A,B){ out <- match(A,B) out <- cbind(out,(A %in% B)*1) out[is.na(out)] <- 0 } ismember(A,B) Output:
out [1,] 0 0 [2,] 0 0 [3,] 2 1 [4,] 1 1 1 Answer
The Matlab function ismember can be translated to R in two ways:
is.element%in%
hence:
ismember(A,B) ---> is.element(A, B) ismember(A,B) ---> A %in% B If you want to include indexing, you can use the match function:
loc <- match(A, B) print(loc) [1] NA NA 2 1 By default, when using match, values with no match return NA but you can change this behavior through the nomatch parameter:
loc <- match(A, B, nomatch = 0) print(loc) [1] 0 0 2 1 In conclusion, your Matlab code:
A = [5 3 4 2]; B = [2 4 4 4 6 8]; [la,loc] = ismember(A,B); can basically be translated to:
A <- c(5,3,4,2) B <- c(2,4,4,4,6,8) la <- is.element(A, B) loc <- match(A, B, nomatch = 0) If you want to obtain both values combined into a single variable you could use:
res <- cbind.data.frame(la = is.element(A, B), loc = match(A, B, nomatch = 0)) print(res$la) [1] FALSE FALSE TRUE TRUE print(res$loc) [1] 0 0 2 1 
