Underscore mixin to enable core R functions

_.R.js

_.mixin({
  sum : function(data){
    return  _.reduce(data, function(memo, num){ return memo + num; }, 0);
  },
  mean : function(data){
  return this.sum(data)/data.length
  },
  median : function(data){
  return this.percentile(data,50);
  },
  range : function(data){
    return [_.min(data),_.max(data)]
  },
  IQR : function(data){
    return this.percentile(data,75) - this.percentile(data,25);;
  },
  summary : function(data){
    var tmp = {};
    tmp['Min'] = this.percentile(data,0);
    tmp['1st_Qu'] = this.percentile(data,25);
    tmp['Median'] = this.percentile(data,50);
    tmp['Mean'] = this.mean(data)
    tmp['3rd_Qu'] = this.percentile(data,75);
    tmp['Max']= this.percentile(data,100);
    return tmp;
  },
  quantile : function(data){
  var tmp = {};
  tmp['0%'] = this.percentile(data,10);
  tmp['25%'] = this.percentile(data,25);
  tmp['50%'] = this.percentile(data,50);
  tmp['75%'] = this.percentile(data,75);
  tmp['100%'] = this.percentile(data,100);
  return tmp;
  },
  percentile : function(data,p){
    if (p===100){return _.max(data)}
    if (p===0){return _.min(data)}
    var v = _.sortBy(data,function(n){return n});
    var h = ((v.length-1)*(p/100));
    return v[Math.floor(h)]+((h-Math.floor(h))*(v[Math.floor(h)+1]- v[Math.floor(h)]))
  },
  weighted_mean : function(data,weight){
    if(data.length !== weight.length){return null}
      var sum = 0;
    _.each(data,function(d,i){
      sum += d*weight[i]
    })
    return sum
  },
  pow : function(data,p){
    var tmp = [];
    _.each(data, function(d,i){
      tmp.push(Math.pow(d,p))
    })
    return tmp
  },
  sbtr : function(data,s){
    var tmp =[];
    _.each(data, function(d,i){
      tmp.push(d - s);
    })
    
    return tmp
  },
  mrt : function(xdata,ydata){
    var tmp =[];
    _.each(xdata, function(d,i){
      tmp.push(xdata[i]*ydata[i]);
    })
    return tmp
  },
  abs : function(data){
    var tmp = [];
    _.each(data, function(d,i){
      tmp.push(Math.abs(d));
    })
    return tmp
  },
  sd : function(data){
    return Math.sqrt(this.vari(data))
  },
  mad : function(data){
    return this.median(this.abs(this.sbtr(data,this.median(data)))) * 1.4826
  },
  cor : function(xdata,ydata){
    if(xdata.length !== ydata.length){return null}
    return this.cov(xdata,ydata) / (Math.sqrt(this.sum(this.pow(this.sbtr(xdata,this.mean(xdata)),2)))*Math.sqrt(this.sum(this.pow(this.sbtr(ydata,this.mean(ydata)),2))))
  },
  cov : function(xdata,ydata){
    if(xdata.length !== ydata.length){return null}
    return this.sum(this.mrt(this.sbtr(xdata,this.mean(xdata)),this.sbtr(ydata,this.mean(ydata))))
  },
  vari : function(data){
    return this.sum(this.pow(this.sbtr(data,this.mean(data)),2))/(data.length-1)
  }
});