How to create an array of objects with a for loop

Question

I have a array of objects called listData that I would like to call certain information from into a separate called markers.

var markers = [];
for(let i=0;i<listData.length;i++){
    markers.push({
        latitude:this.state.listData[i].geometry.location.lat,
        longitude:this.state.listData[i].geometry.location.lng,
        title:this.state.listData[i].name
    });
}

but it is not working.

The variable is listData or this.state.listData? Check the for conditions — Pablo Lozano
– Pablo Lozano, Commented Aug 6, 2016 at 7:23
Why do you want to push the state into another object. Can't you just use the state as it is in the render or do you need to pass it down as props to a child component? — Edgesoft
– Edgesoft, Commented Aug 6, 2016 at 7:44

james emanon · Accepted Answer · 2016-08-06 07:40:19Z

3

I like to use "map" for such data returns. Nothing wrong with what others posted, I just like this concise syntax a bit better. I am assuming you are referencing the initially value incorrectly. You didn't use this.state.listData in your loop.

var markers = this.state.listData.map(function(v){
    return {
       latitude:v.geometry.location.lat,
       longitude:v.geometry.location.lng,
       title:v.name
    }
})

answered Aug 6, 2016 at 7:40

james emanon

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Comments

Christos · Accepted Answer · 2016-08-06 07:23:46Z

0

From your code, I assume that you need something like the following:

for( let i=0; i < listData.length; i++ ){
    markers.push(
    {
        latitude: listData[i].geometry.location.lat,
        longitude: listData[i].geometry.location.lng,
        title: listData[i].name
    }
);

You just want to loop through listData and add for each item of this array (or array like object) a new object to the markers array. So I don't get why you used this.state to access the listData.

answered Aug 6, 2016 at 7:23

Christos

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Comments

M.Tanzil · Accepted Answer · 2016-08-06 07:30:49Z

0

Try this, i think this is what you want.

Remove this and start the hierarchy from state, if its not helping you can remove both this.state and start afterwords.

var markers = [];

for(var i = 0; i < 5; i++){
 markers.push(
   {
    latitude:'0123',
    longitude:'0345' 
   });
}

console.log(markers);

Change and Add values as you desire for yourself.

edited Aug 6, 2016 at 7:30

answered Aug 6, 2016 at 7:25

M.Tanzil

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