I am trying to follow the BiSeq vignette with my own data, but I am confused on how to complete step 4.4. The vignette has this:

## Both resampled groups should have the same number of
## cancer and control samples: 
predictedMethNull <- predictedMeth[,c(1:4, 6:9)]

I don't understand what the c(1:4, 6:9) section of the code refers to. My current thoughts are that it refers to the columns of cancer and control data, but I'm not sure if this is correct. If it is correct, a follow up question I have is if the numbers have to be in that order specifically (i.e. why not [,c(6:9, 1:4)])?

I appreciate any help.