Re: [R] matrix help (first occurrence of variable in column)

Is this what you are looking for: > mdat3 sp.1 sp.2 sp.3 sp.4 sp.5 T110010 T210010 T311100 T410111 > > # create a matrix of when species first appeared > first <- apply(mdat3, 2, function(x) (cumsum(x == 1) > 0) + 0

Re: [R] matrix help (first occurrence of variable in column)

On Wed, May 18, 2011 at 9:49 PM, jim holtman wrote: > Is this what you were after: > >> mdat <- matrix(c(1,0,1,1,1,0), nrow = 2, ncol=3, byrow=TRUE, > +               dimnames = list(c("T1", "T2"), > +                               c("sp.1", "sp.2", "sp.3"))) >> >> mdat >   sp.1 sp.2 sp.3 > T1    

Re: [R] matrix help (first occurrence of variable in column)

Is this what you were after: > mdat <- matrix(c(1,0,1,1,1,0), nrow = 2, ncol=3, byrow=TRUE, + dimnames = list(c("T1", "T2"), + c("sp.1", "sp.2", "sp.3"))) > > mdat sp.1 sp.2 sp.3 T1101 T2110 > # do 'rle' on each column and see

[R] matrix help (first occurrence of variable in column)

Dear R help, Apologies for the less than informative subject line. I will do my best to describe my problem. Consider the following matrix: mdat <- matrix(c(1,0,1,1,1,0), nrow = 2, ncol=3, byrow=TRUE, dimnames = list(c("T1", "T2"), c("sp.1", "sp.2", "