Delete specific columns

April 2, 2022

I have

F <- structure(c(0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0), .Dim = c(3L, 
5L))

How can I remove from F the columns that have less than 2 consecutive zero?
Thx!

>Solution :

We may use rle to determine the consecutive values i.e. 0 and create a logical condition with lengths by looping over the column (apply, MARGIN = 2)

F[,!apply(F, 2, function(x) with(rle(!x), 
      any(lengths >= 2 & values))), drop = FALSE]

-output

      [,1] [,2]
[1,]    0    0
[2,]    1    1
[3,]    1    1

If it is the opposite, just remove the !

F[,apply(F, 2, function(x) with(rle(!x), 
      any(lengths >= 2 & values))), drop = FALSE]
      [,1] [,2] [,3]
[1,]    1    1    1
[2,]    0    0    0
[3,]    0    0    0