Easy way of counting precision, recall and F1-score in R

Question

I am using an rpart classifier in R. The question is - I would want to test the trained classifier on a test data. This is fine - I can use the predict.rpart<

Answer 1

I noticed the comment about F1 score being needed for binary classes. I suspect that it usually is. But a while ago I wrote this in which I was doing classification into several groups denoted by number. This may be of use to you...

calcF1Scores=function(act,prd){
  #treats the vectors like classes
  #act and prd must be whole numbers
  df=data.frame(act=act,prd=prd);
  scores=list();
  for(i in seq(min(act),max(act))){
    tp=nrow(df[df$prd==i & df$act==i,]);        
    fp=nrow(df[df$prd==i & df$act!=i,]);
    fn=nrow(df[df$prd!=i & df$act==i,]);
    f1=(2*tp)/(2*tp+fp+fn)
    scores[[i]]=f1;
  }      
  print(scores)
  return(scores);
}

print(mean(unlist(calcF1Scores(c(1,1,3,4,5),c(1,2,3,4,5)))))
print(mean(unlist(calcF1Scores(c(1,2,3,4,5),c(1,2,3,4,5)))))