Grouping and Sorting in R

Basically, using R I would like to take a data set that looks like this:

And transform it to look like this:

Notice that the final table groups points by team and then sorts the summary data by the number of points scored. Learning how to do this in R would be a huge time saver.

The two functions you will need … once you have an example … are xtabs and ftable. First we convert an existing table to a dataframe and then note that the counts are now in a variable named “Freq”. Then we re-tabulate to a smaller number of dimensions:

> Tdf <- as.data.frame(Titanic, stringsAsFactors=FALSE)
> str(Tdf)
'data.frame':   32 obs. of  6 variables:
 $ Class   : chr  "1st" "2nd" "3rd" "Crew" ...
 $ Sex     : chr  "Male" "Male" "Male" "Male" ...
 $ Age     : chr  "Child" "Child" "Child" "Child" ...
 $ Survived: chr  "No" "No" "No" "No" ...
 $ Freq    : num  0 0 35 0 0 0 17 0 118 154 ...

> ftable( xtabs(Freq ~ Class+Sex, Tdf) , row.vars=c("Class", "Sex") )
Class Sex        
1st   Female  145
      Male    180
2nd   Female  106
      Male    179
3rd   Female  196
      Male    510
Crew  Female   23
      Male    862

I haven’t gotten very many points for it but I did at one time demonstrate on SO how to do sub-totals and grand totals:

R: calculating column sums & row sums as an aggregation from a dataframe