How do I fill up an array within an object in javascript?

Question

I am getting a little confused. I have the following array of objects:

dataTest.rows = [{
        "rowHeader": "",
        "rowDesc": ["INFO1"],
        "rowVal": [
            ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
        ]
    }, {
        "rowHeader": "",
        "rowDesc": ["INFO2"],
        "rowVal": [
            ["1", "2", "3", "4", "5", "6", "7", "8", "9"]

        ]
    }];

How would I fill up the array within the array rowval with a loop if rowVal, say in object1, was empty?

I tried

for (i=0; i<9; i++){
  (dataTest.rows[0]).rowVal[0][i]=i;
}

Should I completely remove the label 'rowVal', and then add it to the object to rebuild it?

wasn't quite get the question here, all you need is replace all the item in rowVal with same value of index? — Dean
– Dean, Commented Apr 20, 2018 at 1:31
You need to convert the number to a string in your loop - the example you gave contains strings and not numbers. Also "if rowVal, say in object1, was empty", you'd need to create an array first to modify. — ASDFGerte
– ASDFGerte, Commented Apr 20, 2018 at 1:32
Your question just doesn't make sense. What do you mean by 'was empty?' at the end? Do you mean if rowVal had no arrays? — ProEvilz
– ProEvilz, Commented Apr 20, 2018 at 1:39
Please edit your question and show us what you want the data to look like after the loop — ProEvilz
– ProEvilz, Commented Apr 20, 2018 at 1:40

a stone arachnid · Accepted Answer · 2018-04-20 03:23:37Z

1

var dataTest={};
dataTest.rows = [{
        "rowHeader": "",
        "rowDesc": ["INFO1"],
        "rowVal": [[]]
    }, {
        "rowHeader": "",
        "rowDesc": ["INFO2"],
        "rowVal": [[]]
    }];
for (var i=0; i<dataTest.rows.length; i++){
    // iteriates through the dataTest.rows array of objects
    console.log("Entered row %i",i);
    for (var j=1; j<=9; j++){
        // converts number to string
        dataTest.rows[i].rowVal[0][j]=j.toString();
    	  console.log(dataTest.rows[i].rowVal[0][j]);
    }
}

UPDATE: Fixed "dataTest.rows[i].rowVal[0] is undefined."

edited Apr 20, 2018 at 3:23

answered Apr 20, 2018 at 1:48

a stone arachnid

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3 Comments

ApisMel Over a year ago

dataTest.row[i].rowVal[0] is undefined?

a stone arachnid Over a year ago

@ApisMel I fixed that. It needs to have the sub-array included.

ApisMel Over a year ago

cool! thanks for helping.. this is working great.. now i can go to the next step.. get the data from a json file

Muskett · Accepted Answer · 2018-04-20 01:51:23Z

0

You can use the .forEach() Array method to loop through every item in array X and push it into array Y.

let dataTest= [{
    "rowHeader": "",
    "rowDesc": ["INFO1"],
    "rowVal": []
}, 

{
    "rowHeader": "",
    "rowDesc": ["INFO2"],
    "rowVal": [
        ["1", "2", "3", "4", "5", "6", "7", "8", "9"]

    ]
}];

dataTest[1].rowVal.forEach(number => {
                dataTest[0].rowVal.push(number)
                })

In this example, the forEach function runs through every item in the dataTest[1].rowVal and pushes everything inside into the array in dataTest[0].rowVal, which should achieve what you're asking.

edited Apr 20, 2018 at 1:51

answered Apr 20, 2018 at 1:47

Muskett

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2 Comments

Dean Over a year ago

what if both array are empty.

Muskett Over a year ago

You can run a for loop before the forEach function, where i = 1 and the second argument is i < X, where X is the top end of the range.

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