Develop Reference

Javascript returns only keys but not values

The following is the data from the source file:
{
"dubbuseqchapter+block#a7a5931f68d0482eaff2b7c9f9684e47": {
"category": "chapter",
"children": [
"dubbuseqsequential+block#968513c8f0cc4249b7cfc2290ac967dc",
"dubbuseqsequential+block#f7f730a478144a74bd127f996d6dc4f5",
"dubbuseqsequential+block#91a0d5d7cd9649a3bdf057400e0a1c96",
"dubbuseqsequential+block#28b2b171b6734b13af29735796c5ad5a",
"dubbuseqsequential+block#192a150c8aab43b9bd236773ba60b414",
"dubbuseqsequential+block#26b3464dad42460ea66f9afe89770065"
],
"metadata": {
"display_name": "Introduction course orientation"
}
},
"dubbuseqchapter+block#b2451e9195c5466db8b66f53ed06c9fd": {
"category": "chapter",
"children": [
"dubbuseqsequential+block#c95826a16f71405ba58319d23d250fc4",
"dubbuseqsequential+block#fe4e3b8b7cdd4fa0b9fe9090223b7125",
"dubbuseqsequential+block#44bbdee625dc465ebe725d2126ed0662",
"dubbuseqsequential+block#8d4daba07d4443f3b2a0b2506280ee2c",
"dubbuseqsequential+block#c68d9d3ba7de45b1b0770085e4f1f286",
"dubbuseqsequential+block#ccdca5b2aca94dbdabb3a57a75adf3fa"
],
"metadata": {
"display_name": "Module closing section"
}
}
}
The following javascript brings the top key values (i.e dubbuseqchapter+block#a7a5931f68d0482eaff2b7c9f9684e47,dubbuseqchapter+block#b2451e9195c5466db8b66f53ed06c9fd )
Javascript code
var obj = JSON.parse(jContent);
var keys = Object.keys(obj);
for (var i = 0; i < keys.length; i++) {
var row = createRowCopy(getOutputRowMeta().size());
var idx = getInputRowMeta().size();
row[idx++] = keys[i];
// Alert (keys.length);
putRow(row);
}
However, I am unable to get the values of the keys..(i.e. Category, Children and metadata) in this example.
I have tried Objects.values() but it returns null or object object in the Alert.

keys is an array of strings, each string being a property name.
You get the value for a property name in the usual way:
object[property_name]
i.e.
var value = obj[keys[i]];

this code shows how to navigate into parsed JsonData
var obj = JSON.parse(textJson);
var keys = Object.keys(obj);
console.log(obj[keys[0]].metadata.display_name);
this will print : Introduction course orientation

Or even this way to retrieve your subProperties
var obj = JSON.parse(textJson);
var keys = Object.keys(obj);
for (var i = 0; i < keys.length; i++){
console.log(keys[i]);
var subKeys = Object.keys(obj[keys[i]]);
for (var j = 0; j < subKeys.length; j++) console.log(subKeys[j] + " --> " + obj[keys[i]][subKeys[j]]);
}

How to iterate over an array in an array

I want to iterate over my 'areasarray' in the array 'areas' dataprovider array,
I have no idea how to loop over an array in an array, I've tried several tries with for-loops but none of it succeeded.
this is amCharts Maps framework.
var areasarray = {};
//get JSON File
$(function getData() {
var url = "../assets/document.json";
$.ajax({
url: url,
dataType: 'json',
success: function (data) {
console.log(data);
for (var i = 0; i < data.fact.length; i++) {
if (inverseCountryCodes[data.fact[i].dims.COUNTRY] != null) {
areasarray[i] = {
"id": inverseCountryCodes[data.fact[i].dims.COUNTRY],
"value": data.fact[i].Value,
"info": "Verkeersdoden per 100 000 inwoners: " + data.fact[i].Value
}
}
}
//console.log(areasarray);
//Map initialiseren
var map;
map = new AmCharts.AmMap();
map.colorSteps = 20;
var dataProvider =
{
mapVar: AmCharts.maps.worldLow
areas: [
{
id: "BE",
value: 10,
info: "Verkeersdoden ..."
}
]
};
console.log(dataProvider);
map.areasSettings = {
autoZoom: true,
selectedColor: "#338DAB"
};
map.dataProvider = dataProvider;
var valueLegend = new AmCharts.ValueLegend();
valueLegend.right = 10;
valueLegend.minValue = "little";
valueLegend.maxValue = "a lot!";
map.valueLegend = valueLegend;
map.addListener("clickMapObject", function (event) {
document.getElementById("info").innerHTML = '<p><b>' + event.mapObject.title + '</b></p><p>' + event.mapObject.info + '</p>';
});
map.mouseWheelZoomEnabled = true;
map.write("mapdiv");
}
});
});

If you want to iterate over areasarray which is actually an object and not an array you should look into using a for...in loop
For iterating over arrays within arrays, one approach would be to nest for loops
for(var i = 0; i < array1.length; i++) {
for(var j = 0; j < array2.length; j++) {
// do something
}
}
It's not clear to me what you mean by "array in an array" in this context and it would help if you provided more information about what exactly you are trying to accomplish

I would try a nested loop. Here is an example of creating an array of arrays and then looping through each.
var matrix = []
matrix[1] = []
matrix[1][1] = "foo"
matrix.forEach(function(column){
column.forEach(function(cell){
console.log(cell);
});
});

var areasarray = {}; means it's an object, not an array.
To iterate through each items in this object, try this.
var keys = Object.keys(areasarray);
keys.forEach(function(k) {
// you can access your item using
// k is the property key
console.log(areasarray[k]);
console.log(areasarray[k].id);
console.log(areasarray[k].value);
console.log(areasarray[k].info);
});
Not sure why you chose to create areasarray as an object.
If you wanted to, you could have defined it as:
var areasarray = [];
Then when adding to the array you use:
areasarray.push({
"id": inverseCountryCodes[data.fact[i].dims.COUNTRY],
"value": data.fact[i].Value,
"info": "Verkeersdoden per 100 000 inwoners: " + data.fact[i].Value
});
So later on, you can simply do:
for (var i = 0; i < areasarray.length; i++) {
console.log(areasarray[i]);
console.log(areasarray[i].id);
console.log(areasarray[i].value);
console.log(areasarray[i].info);
}
Note: in the above code, i is an index, where in the object block code, k is a key to the object.

Use nested loops.
Example:
var a1=["1","2","3","4","5","6","7"];
var a2=["a","b","c","d","e"];
for(var i=0;i<a1.length;i++) //loop1
{
console.log(a1[i]);
for(var j=0;j<a2.length;j++) //loop2
{
console.log(a2[j]);
}
}
Sample Output:
1st iteration of loop1:
1abcde
2nd iteration of loop1:
2abcde
and so on...
For every iteration of loop1,loop2 iterates 4 times(j<5).
Hoping I got your question right...This could be an answer.!

Comparing an Array with an Objects' Array in JavaScript

I am new to JavaScript and wondering how can I compare an array with another array consists of JavaScript objects.
The array is a series of sorted time in the "YYYY-MM-DD" format.
The array of objects missed some price values of several days.
I want to find the missed value and assign it as "NULL".
For example, I have an array as:
array = ['2014-10-09','2014-10-10','2014-10-11','2014-10-12'];
and an array with objects as:
objArray = [{
date:"2014-10-09",
price:"100"
},
{
date:"2014-10-10",
price:"99"
},
{
date:"2014-10-12",
price:"102"
}];
I want to get the price array in this way:
priceResult = [100, 99, "NULL", 102];
What would be the most efficient way without using other libraries? I wanted to see if anyone had a more elegant solution. I deeply appreciate your help.

You can create a lookup set from the object array, then you can use that to translate the dates to prices.
This scales well, as it is an O(n+m) solution rather than the O(n*m) solution that you get if you use a loop in a loop to find the prices.
var array = ['2014-10-09','2014-10-10','2014-10-11','2014-10-12'];
var objArray = [{ date:"2014-10-09", model:"A", price:"100" },{ date:"2014-10-10", model:"A", price:"99" },{ date:"2014-10-12", model:"A", price:"102" }];
var lookup = {};
for (var i = 0; i < objArray.length; i++) {
lookup[objArray[i].date] = parseInt(objArray[i].price, 10);
}
var priceResult = [];
for (var i = 0; i < array.length; i++) {
if (lookup.hasOwnProperty(array[i])) {
priceResult.push(lookup[array[i]]);
} else {
priceResult.push('NULL');
}
}
// output result in StackOverflow snippet
document.write(JSON.stringify(priceResult));
Note: Instead of the string 'NULL' you might want to use the value null instead, as it is generally easier to handle.

lodash is the best library for this. But you did say "without using other libraries", so you will need to do it natively.
The easiest way to do it is nested for loops:
var i, j, d, res = [];
for (i=0; i<dateArray.length; i++) {
d = dateArray[i];
for (j=0; j<objArray.length; j++) {
if (objArray[j] && objArray[j].date && objArray[j].date === d) {
res.push(objArray[j].price);
j = objArray.length; // don't waste energy searching any more, since we found it
}
}
}
// res now contains all you wanted
If objArray is really big, and you don't want to search it multiple times, then you could turn it into an object indexed by date:
var i, obj = {}, d, res = [];
for (i=0; i<objArray.length; i++) {
if (objArray[i] && objArray[i].date) {
obj[objArray[i].date] = objArray[i];
}
}
for (i=0; i<dateArray.length; i++) {
d = dateArray[i];
res.push(obj[d] ? obj[d].price : null : null);
}
// res now contains all you wanted

Loop trough the object and search for the date in your array
// Add contains to array proto: http://css-tricks.com/snippets/javascript/javascript-array-contains/
var priceResult = [];
for(var i in objArray) {
if(dateArray.contains(objArray[i].date)) priceResult.push(objArray[i].date));
}
console.log('matches:', priceResult);

This function will give you map of all individual arrays in your object array
function getArrayMap(array) {
var map={}
for(var i=0;i<array.length;i++){
var o = array[i];
for(var k in o){
if(!map[k]){
map[k]=[];
}
map[k].push(o[k]);
}
}
return map;
}
you can use it like -
var map = getArrayMap(objArray);
console.log(map["date"]);//date array
console.log(map["price"]);//price array
console.log(map["model"]);//model array

If i am understanding your question correctly, for all the values in array, you want to check the objArr and find the price for each date, and if not found u want to inset null. If this is what you want, then following will help
var found= false;
var list=[];
for(var i=0; i< dateArray.length; i++)
{
for(var j=0; j< objArray.length; j++)
{
if(objArray[j].date == dateArray[i])
{
list.push(objArray[j].price);
found = true;
}
}
if(!found)
{
list.push("null");
}
found = false;
}
alert(list);

(I'm going to call your first array dates rather than array, to avoid confusion.)
There are basically two options:
Loop through your dates array and, for each entry, loop through the objArray looking for a match, and when found add to your priceResult array, or
Build a map from your objArray, then loop through yourdatesarray once, building thepriceResult` array.
Looping and Looping
You can loop through your dates array using forEach, and you can use Array#some to find out whether your objArray contains the date and add to priceResult if so (it's an ES5 feature, but you can polyfill it for really old browsers):
var priceResult = [];
dates.forEach(function(date) {
objArray.some(function(object) {
if (object.date == date) {
priceResult.push(object.price);
return true;
}
});
});
Array#some keeps looping until you return true, which is why we do that when we find the firs tmatch. That's why I say this is "looping and looping," even though we only write one loop, the other is within Array#some.
var dates = ['2014-10-09', '2014-10-10', '2014-10-11', '2014-10-12'];
var objArray = [
{
date: "2014-10-09",
model: "A",
price: "100"
},
{
date: "2014-10-10",
model: "A",
price: "99"
},
{
date: "2014-10-12",
model: "A",
price: "102"
}
];
// Do it
var priceResult = [];
dates.forEach(function(date) {
objArray.some(function(object) {
if (object.date == date) {
priceResult.push(object.price);
return true;
}
});
});
snippet.log(priceResult.join(", "));
<!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>
Mapping and Looping
First, create a map of prices by date:
var prices = {};
objArray.forEach(function(object) {
prices[object.date] = object.price;
});
...then create your results:
var priceResult = [];
dates.forEach(function(date) {
if (prices.hasOwnProperty(date)) {
priceResult.push(prices[date]);
}
});
var dates = ['2014-10-09', '2014-10-10', '2014-10-11', '2014-10-12'];
var objArray = [
{
date: "2014-10-09",
model: "A",
price: "100"
},
{
date: "2014-10-10",
model: "A",
price: "99"
},
{
date: "2014-10-12",
model: "A",
price: "102"
}
];
// Create the map
var prices = {};
objArray.forEach(function(object) {
prices[object.date] = object.price;
});
// Create your results:
var priceResult = [];
dates.forEach(function(date) {
if (prices.hasOwnProperty(date)) {
priceResult.push(prices[date]);
}
});
// Show them
snippet.log(priceResult.join(", "));
<!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>

var dates = ['2014-10-09','2014-10-10','2014-10-11','2014-10-12'];
var objArray = [{date:"2014-10-09", model:"A", price:"100" }, {date:"2014-10-10", model:"A", price:"99" }, {date:"2014-10-12", model:"A", price:"102" }];
var val;
var priceResult = [];
for (var a in dates) {
val = null;
for (var b in objArray) {
if (dates[a] == objArray[b].date) {
val = objArray[b].price;
}
}
priceResult.push(val);
}
var dates = ['2014-10-09', '2014-10-10', '2014-10-11', '2014-10-12'];
var objArray = [{
date: "2014-10-09",
model: "A",
price: "100"
}, {
date: "2014-10-10",
model: "A",
price: "99"
}, {
date: "2014-10-12",
model: "A",
price: "102"
}];
var val;
var priceResult = [];
for (var a in dates) {
val = null;
for (var b in objArray) {
if (dates[a] == objArray[b].date) {
val = objArray[b].price;
}
}
priceResult.push(val);
}
// output result in StackOverflow snippet
document.write(JSON.stringify(priceResult));

Try this:
var temp[]
temp= jQuery.grep(objArray , function (n, i)
{
for(j=0;j<dateArray.lenght+j++ )
if( n.date === dateArray[j])
return n.price;
);

dateArray = ["2014-10-09", "2014-10-10", "2014-10-11", "2014-10-12"];
function ObjectExample(date1,model,price)
{
this.date1 = date1;
this.model = model;
this.price = price;
}
var objArray = [new ObjectExample("2014-10-09","A","100"), new ObjectExample("2014-10-10","A","99"), new ObjectExample("2014-10-12","A","102")];
var i = 0;
var priceDate = new Array();
var count = 0;
while(i < dateArray.length)
{
var j = 0;
while(j < objArray.length)
{
if(dateArray[i] == objArray[j].date1)
{
priceDate[count] = objArray[j].price;
break;
}
else priceDate[count] = "NULL";
j = j + 1;
}
i = i + 1;
count++;
}
document.write(priceDate);

javascript increment name of variable

I get an object with partial results of match from database.
[Object { home1=4, away1=3, home2=4, away2=5, home3=6, away3=7, home4=6, away4=5, home5=3, away5=6}]
home1 it's a result of first part of home team,
away1 -> away team, home2 it's a result of second part of home team... etc etc
data in my case is each row, which i get from database.
In rows i have td with class: home1, home2, home3, away1, away2 and there are values of corresponding part of match.
I want to check if value is equal to what I got from database.
Something like this
if ($('.home1') === data[index].home1;
if($('.away2') === data[index].away2;
there should be some loop. I have no idea how to do this, I thought about an array
var array = [
{
home1: data[index].home1,
away1: data[index].away1
},
{
home2: data[index].home2,
away2: data[index].away2
},
{
home3: data[index].home3,
away3: data[index].away3
},
{
home4: data[index].home4,
away4: data[index].away4
},
{
home5: data[index].home5,
away5: data[index].away5
}
]
and then for loop:
for(var X=0; X<5;X++){
homeX == data[index].homeX
}
How can I increment name of variable by eval function? or is there any other solution? I'm very confused.

You can access object properties using operator []:
for(var i=0; i<array.length; i++)
{
var item = array[i];
var homePropertyName = 'home' + (i+1);
//now you can access homeX property of item using item[homePropertyName]
//e.g. item[homePropertyName] = data[index][homePropertyName]
}

Maybe you should use a little different structure which might fit your needs better, like this:
array = [
0: array [
"home": "Text for home",
"away": "Text for away"
],
1: array [
"home": "",
"away": ""
]
// More sub-arrays here
];
You can also initialize it with a for loop:
var array = new Array();
var i;
for (i = 0; i < 4; i++) {
array[i] = [
"home": "",
"away": ""
];
}
Or like this:
array[0]["home"] = "Text for home";
array[0]["away"] = "Text for away";
You can use this structure for the data-array also, and then use a for-loop to go through them both (like if you wish to find an element):
var result = NULL;
for (i = 0; i < array.length; i++) {
if ( (array[i]["home"] == data[index]["home"]) &&
(array[i]["away"] == data[index]["away"])
) {
// Found matching home and away
result = array[i];
break;
}
}
if (result != NULL) {
alert("Found match: " + result["home"] + " - " + result["away"]);
}
else {
alert("No match");
}
PS: Code is not tested, let me know if something is wrong.

you can access global properties in browser via window object like this (fiddle):
value1 = "ONE";
alert( window['value'+1] );
But it is not good design. You should look into how to properly format JSON object.

I have something like this:
for(var i=0; i<2; i++)
{
var item = ARR[i];
for(var x=0;x<5;x++){
var hPropertyName = 'home_p' + (x+1);
var aPropertyName = 'away_p' + (x+1);
item[hPropertyName] = ARR[i][hPropertyName];
item[aPropertyName] = ARR[i][aPropertyName];
}
and it works when i create an array:
var ARR = [
{
home_p1: 4,
away_p1: 5,
home_p2: 8,
away_p2: 9,
home_p3: 2,
away_p3: 1,
home_p4: 5,
away_p4: 3,
home_p5: 3,
away_p5: 2
},
{
home_p1: 6,
away_p1: 1,
home_p2: 1,
away_p2: 2,
home_p3: 3,
away_p3: 4,
home_p4: 5,
away_p4: 6,
home_p5: 3,
away_p5: 2
}
];
but I don't have to create an array, because i have to work on object which I get from database :
[Object { event_id=19328, home_result=3, away_result=2, home_p1=4, away_p1=3, home_p2=1, away_p2=2 ...... }]
I'm only interested in these parameters --> home_p , away_p
I want to push it to my array to looks like ARR. I think i should convert an object which I get to an array

If you are using string name for your attributes then you could try using template literals?
var someObject = {}
for(let i=0 ; i<values.length ; i++){
someObject[`home${i+1}`] = values[i];
}
and if you need it to be ES5 you could just use string concatenation. Below is a working example:
values = [1,2,3,4,5];
let someObject = {};
for(let i=0 ; i<values.length ; i++){
someObject[`value${i+1}`]=values[i];
}
console.log(someObject.value1);
console.log(someObject.value2);
console.log(someObject.value3);
console.log(someObject.value4);
console.log(someObject.value5);

get values in pairs from json array

Firstly, this is my json value i am getting from a php source:
[{"oid":"2","cid":"107"},{"oid":"4","cid":"98"},{"oid":"4","cid":"99"}]
After that, I want to get and oid value along with the corresponding cid value for example, oid=2 and cid=107 at one go, oid=4 and cid=98 at another and so on. I am trying to use jquery, ajax for this.
I have tried many answers for this, like: Javascript: Getting all existing keys in a JSON array and loop and get key/value pair for JSON array using jQuery but they don't solve my problem.
I tried this:
for (var i = 0; i < L; i++) {
var obj = res[i];
for (var j in obj) {
alert(j);
}
but all this did was to return the key name, which again did not work on being used.

So, you have an array of key/value pairs. Loop the array, at each index, log each pair:
var obj = [{"oid":"2","cid":"107"},{"oid":"4","cid":"98"},{"oid":"4","cid":"99"}];
for (var i = 0; i < obj.length; i++) {
console.log("PAIR " + i + ": " + obj[i].oid);
console.log("PAIR " + i + ": " + obj[i].cid);
}
Demo: http://jsfiddle.net/sTSX2/

This is an array that you have //lets call it a:
[{"oid":"2","cid":"107"},{"oid":"4","cid":"98"},{"oid":"4","cid":"99"}]
To get first element :
a[0] // this will give you first object i.e {"oid":"2","cid":"107"}
a[0]["oid"] // this will give you the value of the first object with the key "oid" i.e 2
and so on ...
Hope that helps.
`

Basically what you need is grouping of objects in the array with a property. Here I am giving two functions using which you can do this
// To map a property with other property in each object.
function mapProperties(array, property1, property2) {
var mapping = {};
for (var i = 0; i < data.length; i++) {
var item = data[i];
mapping[item[property1]] = mapping[item[property1]] || [];
mapping[item[property1]].push(item[property2]);
}
return mapping;
}
// To index the items based on one property.
function indexWithProperty(array, property) {
var indexing = {};
for (var i = 0; i < data.length; i++) {
var item = data[i];
indexing[item[property]] = indexing[item[property]] || [];
indexing[item[property]].push(item);
}
return indexing;
}
var data = [{
"oid": "2",
"cid": "107"
}, {
"oid": "4",
"cid": "98"
}, {
"oid": "4",
"cid": "99"
}];
var oidCidMapping = mapProperties(data, "oid", "cid");
console.log(oidCidMapping["2"]); // array of cids with oid "2"
var indexedByProperty = indexWithProperty(data, "oid");
console.log(indexedByProperty["4"]); // array of objects with cid "4"
May not be the exact solution you need, but I hope I am giving you the direction in which you have to proceed.
If you are willing to use other library you can achieve the same with underscorejs