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As a team, answer all the questions the team's members submitted on our course forum. Each team member is responsible for one question. But everyone should work together to come up with a good solution. Your answer should consist of Lodash code and a brief writeup. Utilize _.map, _.filter, _.group ...etc. Do not use any for loop.

It is important for everyone to understand all the solutions and make sure you will be able to independently reproduce these solutions when asked to do so. Coming up, we will incorporate variations of these questions into a future hackathon and you are expected to be capable of reproducing and adapting your solutions.

Which course has the highest enrollment? by Andrew

//for course title
var group = _.groupBy(data, 'CourseTitle');
var coursesEnroll = _.mapValues(group, function(d){
   var enrollNumbers = _.pluck(d, 'N.ENROLL')
   return _.sum(enrollNumbers)
})
var max = _.max(coursesEnroll);
var bigClass =  _.pick(coursesEnroll, function(d){
   return d == max;
});
return bigClass

How many instructors have taught each subject? by Kari

var group = _.groupBy(data, "Subject")

var result = _.mapValues(group, function(n){
	var S = _.pluck(n, "Instructors")
	return _.size(_.uniq(_.flatten(_.map(S, function(x){
		return _.pluck(x,"name")
	}))))
})
return result

Does the instructors tends to give out higher grades if they teach more classes? or the reverse? by Ming

var graded = _.filter(data,function(d){
  return d.hasOwnProperty("AVG_GRD");
})


var smallData = _.map(graded, function(d){
  var avg_grd = d.AVG_GRD;
  var nameArr = _.pluck(d.Instructors, 'name');
  var objArray = _.map(nameArr, function(d){
    var obj = {name:d,AVG_GRD:avg_grd};
    return obj;
  })
  return objArray;
});

var groups = _.groupBy(_.flatten(smallData),'name');

var groups2 = _.map(groups, function(d){
  var avg = _.reduce(d, function(total,e){
    return total+e.AVG_GRD;
  },0)/_.size(d);
  var obj = {classcount:_.size(d),AVG_GRD:avg,name:_.first(d).name}
  return obj;
});
var groups3 = _.groupBy(groups2,'classcount');

var avgbyCount = _.mapValues(groups3, function(d){
  var avg = _.reduce(d, function(total,e){
    return total+e.AVG_GRD;
  },0)/_.size(d);
  var obj = {classcount:_.first(d).classcount,AVG_GRD:avg,instrCount:_.size(d)}
  return obj;
});
return avgbyCount

{
 "1": {
  "classcount": 1,
  "AVG_GRD": 3.282425000000004,
  "instrCount": 800
 },
 "2": {
  "classcount": 2,
  "AVG_GRD": 3.2711051829268296,
  "instrCount": 656
 },
 "3": {
  "classcount": 3,
  "AVG_GRD": 3.30401925391095,
  "instrCount": 277
 },
 "4": {
  "classcount": 4,
  "AVG_GRD": 3.213417266187052,
  "instrCount": 139
 },
 "5": {
  "classcount": 5,
  "AVG_GRD": 3.2277377049180327,
  "instrCount": 61
 },
 "6": {
  "classcount": 6,
  "AVG_GRD": 3.1722222222222216,
  "instrCount": 69
 },
 "7": {
  "classcount": 7,
  "AVG_GRD": 3.202216748768473,
  "instrCount": 29
 },
 "8": {
  "classcount": 8,
  "AVG_GRD": 3.10605,
  "instrCount": 25
 },
 "9": {
  "classcount": 9,
  "AVG_GRD": 3.5538095238095244,
  "instrCount": 7
 },
 "10": {
  "classcount": 10,
  "AVG_GRD": 2.717,
  "instrCount": 2
 },
 "14": {
  "classcount": 14,
  "AVG_GRD": 3.4803571428571427,
  "instrCount": 2
 },
 "15": {
  "classcount": 15,
  "AVG_GRD": 3.5316666666666663,
  "instrCount": 2
 },
 "16": {
  "classcount": 16,
  "AVG_GRD": 3.861875,
  "instrCount": 1
 },
 "20": {
  "classcount": 20,
  "AVG_GRD": 3.304500000000001,
  "instrCount": 1
 },
 "21": {
  "classcount": 21,
  "AVG_GRD": 2.5514285714285716,
  "instrCount": 1
 },
 "22": {
  "classcount": 22,
  "AVG_GRD": 3.185000000000001,
  "instrCount": 1
 },
 "25": {
  "classcount": 25,
  "AVG_GRD": 2.9128,
  "instrCount": 1
 },
 "26": {
  "classcount": 26,
  "AVG_GRD": 3.1234615384615387,
  "instrCount": 1
 },
 "27": {
  "classcount": 27,
  "AVG_GRD": 2.906296296296296,
  "instrCount": 1
 },
 "33": {
  "classcount": 33,
  "AVG_GRD": 2.695757575757576,
  "instrCount": 1
 },
 "39": {
  "classcount": 39,
  "AVG_GRD": 2.733589743589744,
  "instrCount": 1
 },
 "41": {
  "classcount": 41,
  "AVG_GRD": 2.599024390243903,
  "instrCount": 1
 },
 "60": {
  "classcount": 60,
  "AVG_GRD": 2.917166666666667,
  "instrCount": 1
 },
 "64": {
  "classcount": 64,
  "AVG_GRD": 2.375000000000001,
  "instrCount": 1
 }
}

Which department has the lowest enrollment? by John

var group = _.groupBy(data, "CrsPBADept")
var sum = _.mapValues(group, function(n){
	var enroll = _.pluck(n, "N.ENROLL")
	return _.sum(enroll)
})
var min = _.min(sum)
var result = _.pick(sum, function(x){
	return x == min
})
return result

Which subject is most in demand,based on the total number of enrollment? by Sussant

var group = _.groupBy(data, "Subject")
var sum = _.mapValues(group, function(n){
	var enroll = _.pluck(n, "N.ENROLL")
	return _.sum(enroll)
})
var max = _.max(sum)
var result = _.pick(sum, function(x){
	return x == max
})
return result