Javascript Array Help, how to find an item

Question

I am pretty new to JavaScript and am trying to figure out how to find an item in an array. If I have:

var myArray = new Array();
myArray.push({ColumnA:1, ColumnB: 10, ColumnC:100);
myArray.push({ColumnA:1, ColumnB: 20, ColumnC:200);
myArray.push({ColumnA:2, ColumnB: 10, ColumnC:300);
myArray.push({ColumnA:2, ColumnB: 20, ColumnC:400);

If I want to return the ColumnC value for ColumnA = 1 and Column 2 = 20 how do I do so?

You aren't closing your curly brace for creating the objects — Jay Mason, Jan 09 '19 at 19:31
Possible duplicate of [Get JavaScript object from array of objects by value of property](https://stackoverflow.com/questions/13964155/get-javascript-object-from-array-of-objects-by-value-of-property) and [Find object by id in an array of JavaScript objects](https://stackoverflow.com/questions/7364150) and [Find a value in an array of objects in Javascript](https://stackoverflow.com/questions/12462318) — adiga, Jan 09 '19 at 19:32
Possible duplicate of [Find object by id in an array of JavaScript objects](https://stackoverflow.com/questions/7364150/find-object-by-id-in-an-array-of-javascript-objects) — lux, Jan 09 '19 at 19:35

JO3-W3B-D3V · Answer 1 · 2019-01-09T19:36:51.103

Simple, you can use something along the lines of Array.find, it seems like the most logical option, you could also use Array.filter to get multiple results.

var myArray = new Array();
myArray.push({ColumnA:1, ColumnB: 10, ColumnC:100});
myArray.push({ColumnA:1, ColumnB: 20, ColumnC:200});
myArray.push({ColumnA:2, ColumnB: 10, ColumnC:300});
myArray.push({ColumnA:2, ColumnB: 20, ColumnC:400});

var found = myArray.find(function(object) {
  return object.ColumnA == 1 && object.ColumnB == 20;
}); 

var foundMultiple = myArray.filter(function(object) {
  return object.ColumnA == 1 && object.ColumnB == 20;
});

console.log(found);
console.log(foundMultiple);

score 0 · Accepted Answer · answered Jan 09 '19 at 19:35

First I would filter the array based on your criteria

var filteredArray = NECtable430250.filter(function (element) {
    return element.ColumnA == 1 && element.ColumnB == 20
});

//Produces [{ColumnA:1, ColumnB: 20, ColumnC:200}];

Next, you can get the single element in the filteredArray (I would recommend checking that it has at least one element) and get the value for ColumnC.

if(filteredArray.length > 0) {
    var ColumnC = filteredArray[0].ColumnC;
    //do stuff with ColumnC
}

score 0 · Answer 3 · answered Jan 09 '19 at 20:02

Simply find() those two values in the array like so:

 

var myArray = new Array();
myArray.push({ColumnA:1, ColumnB: 10, ColumnC:100});
myArray.push({ColumnA:1, ColumnB: 20, ColumnC:200});
myArray.push({ColumnA:2, ColumnB: 10, ColumnC:300});
myArray.push({ColumnA:2, ColumnB: 20, ColumnC:400});

var yourValue = myArray.find(e => e.ColumnA == 2 && e.ColumnB == 20 ? true : false);
console.log(theValue);

Javascript Array Help, how to find an item

3 Answers3