R/performance_metrics.R
    performanceMeasure.RdQuantify the performance of a classification algorithm. Predictions and truth both have to be binary.
performanceMeasure(pred, obs, perf.method = "f.measure", ...)a logical or numeric, where 0 and FALSE represent control, and, 1 and TRUE represent cases
a logical or numeric, where 0 and FALSE represent control, and, 1 and TRUE represent cases
a character, specifying the method to use. Available
methods can be accessed using perfMethods
additional parameters to methods. see details
a numeric, representing the performance
The F-measure requires the beta parameter which can be specified
  using f.beta which defaults to 1 thereby computing the F1-measure.