[R] Reverse the scoring of some Columns of a Data Set

[Daniel Nordlund]

On 3/8/2017 6:14 AM, AbouEl-Makarim Aboueissa wrote:
> Dear All: goods morning
> 
> Is there is a way to reverse the scoring of the first three columns x1, x2,
> and x3 and keep the original scores for the fourth column x4.
> 
> 
> *Here is an example of the data set:*
> 
> x1 x2 x3 x4
> 2  5   4   4
> 1  1   1   6
> 1  2   1   6
> 2  3   2   4
> 1  2   1   6
> 1  3   1   6
> 2  2   2   5
> 2  1   1   6
> 2  2   4   5
> 5  5   2   1
> 
> I am expecting the output to be:
> x1 x2 x3 x4
> 5  5   2   4
> 2  2   4   6
> 2  1   1   6
> 2  2   2   4
> 1  3   1   6
> 1  2   1   6
> 2  3   2   5
> 1  2   1   6
> 1  1   1   5
> 2  5   4   1
> 
> 
> 
> thank you very much for your help and support
> abou
> ______________________
> AbouEl-Makarim Aboueissa, PhD
> Department of Mathematics and Statistics
> University of Southern Maine
>

  If your data is in a data frame called df, you could do something like 
this:

df[,1:3] <- apply(df[,1:3], 2, function(x) x[length(x):1])


Hope this helps,

Dan

-- 
Daniel Nordlund
Port Townsend, WA  USA