Calculate the difference betwen pairs of consecutive rows in a data frame - R

Question

I have a data.frame in which each gene name is repeated and contains values for 2 conditions:

df <- data.frame(gene=c(\"A\",\"A\",\"B\",\"B\",\"C\",\"C\"),
c         


        

Answer 1

Something like this:

df$up.down <- with( df, ave(count, gene,
                FUN=function(diffs) c("up", "down")[1+(diff(diffs) < 0) ]) )
spltdf <- split(df, df$up.down)

> df
  gene condition count  sd up.down
1    A   control    10 1.0    down
2    A treatment     2 0.2    down
3    B   control     5 0.1      up
4    B treatment     8 2.0      up
5    C   control     5 0.8    down
6    C treatment     1 0.1    down
> spltdf
$down
  gene condition count  sd up.down
1    A   control    10 1.0    down
2    A treatment     2 0.2    down
5    C   control     5 0.8    down
6    C treatment     1 0.1    down

$up
  gene condition count  sd up.down
3    B   control     5 0.1      up
4    B treatment     8 2.0      up