Develop Reference

For each entry in a sub array add values

let b = [];
this.state.sidejobs.forEach((user) => {
console.log(user);
if (!b.hasOwnProperty(user.jobworker)) b[user.jobworker] = 0;
b[user.jobworker] += user.duration;
});
One entry in jobworker has an array with two ids... how do i split it and add the duration respectively.
Name ID Total Hours
Mike Smith 281 5
284,281 5
John Doe 284 21
Chris Smith 283 23

let b = [];
this.state.sidejobs.forEach((user) => {
var jobworkers = user.jobworker.toString().split(",");
for (var i = 0; i < jobworkers.length; i++) {
var worker = jobworkers[i].trim();
if (!b.hasOwnProperty(worker)) b[worker] = 0;
b[worker] += user.duration;
}
});

First of all, is b an array or an object? Or are you using it as both? I suspect you meant for it to be an anonymous object.
let b = {};
Secondly, it would really help to know the exact structure of user.jobworker (eg: call "JSON.stringify(user.jobworker)"). For now, I will assume that the structure of the user object is as follows:
{
name: "Mike Smith",
id: 281,
duration: 5,
jobworker: [284, 281]
}
If that is the case, all you have to do is
let b = {};
this.state.sidejobs.forEach((user) => {
for (var i = 0; i < user.jobworker.length; i++) {
if (!b.hasOwnProperty(user.jobworker[i])) b[user.jobworker[i]] = 0;
b[user.jobworker[i]] += user.duration;
}
});
If instead user.jobworker contains a comma-delimited string of ids (eg: user.jobworker = "284,281") then you will have to split the string first:
this.state.sidejobs.forEach((user) => {
var jobworkers = user.jobworker.split(",");
for (var i = 0; i < jobworkers.length; i++) {
var worker = jobworkers[i].trim();
if (!b.hasOwnProperty(worker)) b[worker] = 0;
b[worker] += user.duration;
}
});

How to simplify this D3 code?

I've got some CSV data that looks like this, showing pass rates by organisation by year:
org,org_cat,2004_passed,2004_total,2005_passed,2005_total,2006_passed,2006_total
GSK,industry,35,100,45,100,55,100
I'm working in D3, and I'd like to end up with a dictionary of organisations like this:
data = {
'GSK': {
'org_cat': 'industry',
'data': [
{ 'year': 2004, 'passed': 35, 'total': 100 },
{ 'year': 2005, 'passed': 45, 'total': 100 },
{ 'year': 2006, 'passed': 55, 'total': 100 }
]
]
}
Most of this is straightforward, but I've got very messy code for the year columns:
var data = {};
allData.forEach(function(d) {
data[d.org] = {
'category': d.org_cat,
'data': []
};
for (var k in d) {
var temp = {};
for (var k in d) {
if (patt.test(k)) {
var res = k.split("_");
if (res[0] in temp) {
temp[res[0]][res[1]] = +d[k];
} else {
temp[res[0]] = {};
temp[res[0]][res[1]] = +d[k];
}
}
}
var tempArr = [];
for (var y in temp) {
var tempDict = {};
tempDict.year = y;
tempDict.passed = temp[y].passed;
tempDict.total = temp[y].total;
tempArr.push(tempDict);
}
// TODO: sort by year in case the keys got shuffled
data[d.org].data = tempArr;
}
});
Is there a way to simplify this horrid code?
It's safe to assume that each row is a unique organisation.

I don't see why you need D3 to do this. You're code doesn't use it either. Here's how I would do it, I'm sure there's another simpler way but it may help you either way :
Jsfiddle : https://jsfiddle.net/thatOneGuy/dnvheznk/1/
I converted the data to JSON to use with JSFiddle, but you already know how to loop through CSV so just overwrite line 14 :
for (var i = 0; i < data.length; i++) { //loop through data array (this is so you can use this on a bigger sized array)
To your loop :
allData.forEach(function(d, i) { //but add the 'i' to index
Here is full commented code with converted JSON data :
var data = [{ //data set converted to JSON for easier use
"org": "GSK",
"org_cat": "industry",
"2004_passed": 35,
"2004_total": 100,
"2005_passed": 45,
"2005_total": 100,
"2006_passed": 55,
"2006_total": 100
}];
var newData = {}; //new data container
for (var i = 0; i < data.length; i++) { //loop through data array (this is so you can use this on a bigger sized array)
var thisObj = {}; //create empty object
thisObj.org_cat = data[i].org_cat; //set org_cat
thisObj.data = []; //set data to empty array to populate later
for (var key in data[i]) { //loop through data[i]
if (key != 'org' && key != 'org_cat') { //check this key is not org or org_cat
var thisData = {}; //create empty data object
var thisYear = key.toString().substring(0, 4); //get year by using substring
thisData.year = thisYear; //set year
thisData.passed = data[i][thisYear + '_passed']; //set passed at this year
thisData.total = data[i][thisYear + '_total']; //set total at this year
thisObj.data.push(thisData); //push this data to data array
}
}
var uniqueDates = []; //set empty array to use to remove duplicate items in data array
for (var j = 0; j < thisObj.data.length; j++) { //loop through data array created earlier
if (uniqueDates.indexOf(thisObj.data[j].year) < 0) { //if this year doesn't exist in unique array above, push it in
uniqueDates.push(thisObj.data[j].year); //push it in
} else {
thisObj.data.splice(j--, 1); //remove duplicate data
}
}
newData[data[i].org] = thisObj; //set data # current org to be object created above
}
console.log('newData', newData) //log new data

JavaScript module pattern gives unexpected results

I am just messing around with generating random human names in JS. I wanted to also practice using the module pattern but I can't get my function to return a normal array.
What I want to save is how often a letter (or set of letters) shows up after another letter.
So with 'jacob' and 'jarod' I should see that the letter 'a' came after the letter 'j' 2 times like this: myArray[j][a] //2
BUT what I have instead somehow turned the array into a set of properties and to figure out that 'a' comes up 2 times I have to check it this way : myArray.j.a //2
can someone explain why this is and how I can fix it?
var names = ['jacob', 'cameron', 'zach', 'lake', 'zander', 'casey', 'carl', 'jeff', 'jack', 'jarod', 'max', 'cat', 'mallory', 'dana', 'hannah', 'stu', 'abrham', 'isaac'];
var probabilities = (function(){
var nextLetterProbability = [];
function addProbability(index, letters){
if(nextLetterProbability[index] !== undefined){
if(nextLetterProbability[index][letters] !== undefined){
nextLetterProbability[index][letters] = nextLetterProbability[index][letters] + 1;
}
else
nextLetterProbability[index][letters] = 1;
}
else{
nextLetterProbability[index] = [];
nextLetterProbability[index][letters] = 1;
}
}
return {
learn:function(names, chainLength){
for (var i = 0; i < names.length; i++) {
var name = names[i];
for (var j = 0; j < name.length - chainLength; j++) {
var start = name[j];
var next = name.slice(j + 1, j + chainLength + 1)
addProbability(start, next);
};
};
},
getLearnedArray:function(){
return nextLetterProbability;
}
}
})();

var nextLetterProbability = []; needed to be var nextLetterProbability = {}; because it is an associative array and is handled as an object.

How do you sort multiple objects that contain arrays representing scores?

Given an array of objects like this:
competitors = [{
name: "Alice",
scores: [3,7,8,2,5]
}, {
name: "Bob",
scores: [4,4,5,6,8]
}, {
name: "Carol",
scores: [5,3,2,7,6]
}];
Given that lower scores are better, how can I sort them (rank them 1-3) such that the winner is the one who wins the most comparisons within each index?
For example, with Alice, Bob, and Carol, Alice should win because she has 3 wins (3<4<5, 2<6<7, 5<6<8) out of a possible 5.
A more complicated example is
competitors = [{
name: "Dave",
scores: [8,1,1,8,4]
}, {
name: "Eve",
scores: [1,5,4,5,2]
}, {
name: "Frank",
scores: [6,2,3,4,7]
}];
Here, Frank loses (1 win: 4<5<8), while Dave (2 wins: 1<2<5, 1<3<4) and Eve (2 wins: 1<6<8, 2<4<7) tie. So repeating the process with just Dave and Eve, you can break the tie. Eve wins the tie-breaker with 3 wins, 2 losses. The final ranking is Eve, Dave, Frank.
I will always know ahead of time the number of scores each competitor has (let's call it numJudges), as well as the range of possible scores (let's call it 1-numCompetitors). I'm also not concerned about browser support, other than webkit's javascript engine, so that means support for ECMAScript 5 and some 6 (es5-compat-table) like the array functions every, map, filter, and reduce.

I find it often helps breaking a a big task like this down into stages. I doubt if it's efficient, but it might be useful to you.
To begin: get an array containing the results for each competitor:
function getScores() {
return competitors.map(function (el) {
return el.scores;
});
}
var scores = getScores();
Then pull out the individual game information:
function getGames(scores) {
var games = [];
for (var i = 0, l = scores[0].length; i < l; i++) {
games.push(scores.map(function (el) {
return el[i];
}));
}
return games;
}
var games = getGames(scores);
Find the winners of each game:
function findWinners(games) {
return games.map(function (el) {
return el.indexOf(Math.min.apply(null, el));
});
}
var winners = findWinners(games);
And finally, update each competitor with their results.
function applyWinners(winners) {
winners.forEach(function (el, i) {
var competitor = competitors[el];
if (!competitor.results) competitor.results = [];
competitor.results.push(i);
});
}
applyWinners(winners);
console.log(competitors) // Alice wins [0, 3, 4], Carol wins [1, 2]
Fiddle

Note: I prefer #Tibos answer but this one is simpler.
You can use a sorting function (Array.sort):
function getWins(competitors, competitor) {
var scores = competitor.scores;
var wins = 0;
for (var i = 0, n = scores.length; i < n; i++) {
var win = true;
for (var j = 0, m = competitors.length; j < m; j++) {
// Do not compare the competitor with himself
if (competitors[j] !== competitor) {
// Do not count a win if someone beat him
if (competitors[j].scores[i] > scores[i]) {
win = false;
break;
}
}
}
if (win) {
wins++;
}
}
return wins;
}
// Sort competitors according to their wins
competitors.sort(function(a, b) {
return getWins(competitors, b) - getWins(competitors, a);
});

A special compare function that computes the wins on the next level for a tie can do this:
function compareArray(a, b) {
for (var i=0; i<a.length && i<b.length; i++)
if (a[i] != b[i])
return a[i] - b[i];
return a.length-b.length;
}
function addWins(c) {
var w = new Array(c.length);
for (var i=0; i<numJudges; i++) {
// if two players have scored equally, the first will win
var l = 0;
for (var j=1; j<c.length; j++)
if (c[j].scores[i] < c[l].scores[i])
l = j;
w[l] = (w[l]||0)+1;
}
for (var i=0; i<c.length; i++)
c[i].wins.push(w[i]||0);
}
for (var i=0; i<competitors.length; i++)
competitors[i].wins = [];
competitors.sort(function(a, b) {
var samelevel = competitors;
do {
var o = - compareArray(a.wins, b.wins)
if (o != 0)
return o;
var len = samelevel.length;
samelevel = samelevel.filter(function(c) {
return compareArray(c.wins, a.wins) == 0;
})
addWins(samelevel);
} while (samelevel.length < len);
return - compareArray(a.wins, b.wins);
});

Count distinct elements in array

I have data that comes from my server to datatables.
I'm successfully populating my table but in footer callback I want to do some statistics.
Lets say I have data like so:
var data = [{
date: '2013-05-12',
holiday: "One type of holiday",
dayType: "Weekend"
}, {
date: '2013-05-13',
holiday: "Another type",
dayType: "Weekend"
}, {
date: '2013-05-14',
holiday: "Another type",
dayType: "Work"
}, {
date: '2013-05-15',
holiday: "",
dayType: "Work"
}];
I would like to count number of days with different holidays.
Here is result I would like to get:
var summary= [
{
"One type of holiday": {
"work": 0,
"weekend": 1
}
},
{
"Another type": {
"work": 1,
"weekend": 1
}
}];
I've created a very simple code to simply aggregate holidays:
for (var i = 0; i < data.length; i++) {
//console.log(data[i].holiday);
/*other stuff here*/
if (data[i].holiday.length > 0)
summary[data[i].holiday] = summary[data[i].holiday] + 1 || 1;
}
but this gives me invalid results, because in my data array holiday contains spaces.
I need a way to fix this and to split holidays based on dayType.
MY SOLUTION:
My version of answer:
var summary = {}, d, tmp, type;
for (var i = 0; i < data.length; i++) {
var d = data[i];
if (d.holiday.length > 0) {
type = d.dayType == 'Weekend' || d.dayType == 'Free' ? 'Weekend' : 'Work';
tmp = summary[d.holiday];
if (!tmp) {
tmp = {
Weekend: 0,
Work: 0
};
summary[d.holiday] = tmp;
}
summary[d.holiday][type] += 1;
}
}
Because this is modified version of #Arun answer I'm not posting this as standalone answer.
I find my version easier to understand, hope someone find's it useful.

Try
var summary = [], summaryMap = {}, d, map, m;
for (var i = 0; i < data.length; i++) {
var d = data[i];
map = summaryMap[d.holiday];
if(!map){
map = {
Work: 0,
Weekend: 0
};
m = {};
m[d.holiday] = map;
summary.push(m);
summaryMap[d.holiday] = map;
}
map[d.dayType] += 1;
}
console.log(summary);
console.log(JSON.stringify(summary));
Demo: Fiddle

go for
console.log(Object.keys(summary).length);
instead of
console.log(summary.length);
Because you can get the number of elements in a js object by using the length attribute.
note: using Object.keys may lead you to browser compatibility issues. As its supported form IE 9 and Firefox 4. See more info in this MDN article.
you can find more info and solutions for this problem in this answer.
see the updated fiddle.

Here's my attempt:
var summary = [];
var holidayTypes = [];
var dayTypes = [];
//first work out the different types of holidays
for (var i = 0; i < data.length; i++) {
if(holidayTypes.indexOf(data[i].holiday) == -1){
//this is a new type of holiday
holidayTypes.push(data[i].holiday);
}
if(dayTypes.indexOf(data[i].dayType) == -1){
//new type of day.
dayTypes.push(data[i].dayType);
}
}
console.log('types of holiday: ' + JSON.stringify(holidayTypes));
console.log('types of day: ' + JSON.stringify(dayTypes));
for(index in holidayTypes){
var typeobj = {};
//create an object for each type of holiday
typeobj[holidayTypes[index]] = {};
for(index2 in dayTypes){
//initialize a count for each type of day
typeobj[holidayTypes[index]][dayTypes[index2]] = 0;
//iterate through the data and count the occurrences where the day AND holiday match.
//if they do, iterate the value.
for (var j = 0; j < data.length; j++){
if((data[j].holiday == holidayTypes[index])
&& (data[j].dayType == dayTypes[index2])){
typeobj[holidayTypes[index]][dayTypes[index2]]++;
}
}
}
summary.push(typeobj);
}
console.log(JSON.stringify(summary));
Fiddle here
Output:
[{"One type of holiday":{"Weekend":1,"Work":0}},{"Another type":{"Weekend":1,"Work":1}},{"":{"Weekend":0,"Work":1}}]
It works but is unlikely to be as efficient as the guys above!