nl_tokens: convert an array of features to a single line in SVM - light format . The line starts with a space .
pl_tokens: function featureArrayToFeatureString ( features , bias , firstFeatureNumber ) { if ( ! Array . isArray ( features ) ) throw new Error ( "Expected an array, but got " + JSON . stringify ( features ) ) var line = ( bias ? " " + firstFeatureNumber + ":" + bias : "" ) ; for ( var feature = 0 ; feature < features . length ; ++ feature ) { var value = features [ feature ] ; if ( value ) line += ( " " + ( feature + firstFeatureNumber + ( bias ? 1 : 0 ) ) + ":" + <mask> . toPrecision ( 5 ) ) ; } return line ; }