Delete row based on the value of the rows above

Question

I have a the following data set:

data <- cbind(c(1,2,3,4,5,6,7,8,9,10,11),c(1,11,21,60,30,2,61,12,3,35,63))

I would like to select the rows for which the number in the second column is greater than the highest number reached up to that point. The result should look like this.

    [,1]    [,2]
[1,]    1   1
[2,]    2   11
[3,]    3   21
[4,]    4   60
[5,]    7   61
[6,]    11  63

Answer 1

You want to try cummax:

> d[ d[,2] == cummax(d[,2]) ,]
     [,1] [,2]
[1,]    1    1
[2,]    2   11
[3,]    3   21
[4,]    4   60
[5,]    7   61
[6,]   11   63

PS. data is an internal R function, so, since R variables and functions share the namespace (R design was influenced by Scheme, which is a "Lisp-1"), your variable shadows the system function.

Answer 2

The cummax function should work well

data[ data[,2]==cummax(data[,2]),] 

returns

     [,1] [,2]
[1,]    1    1
[2,]    2   11
[3,]    3   21
[4,]    4   60
[5,]    7   61
[6,]   11   63

as desired.