Finding a Diff within a Dataframe columns

I see that others have already responded, but will add my point of
view.  You indicated that you wanted to take the difference between
pairs of columns and did not specify exactly how many there were; in
your example there were 4 columns (2 pairs).  If there were only two,
then the solution from Dennis would be the way to go because it is
explicit in what has to be done.  I just created a list of the "odd"
columns [seq(from = 1, by = 2, length = ncol(x) %/%2)] trying to take
care of any odd number of columns.  This was then used in the 'sapply'
to iterate over the columns.

Hi jholtman,

Thanks a ton it just worked. if you dont mind can you explain the code it a
little
sapply(seq(from = 1, by = 2, length = ncol(x) %/% 2), function(a){
+ ? ? x[[a]] - x[[a + 1]]
+ })

wat is the purpose of double percent sign and is the sapply the function we
generally use for the Dataframe?

Thanks
Ramya
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Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?