What am I doing wrong in this javascript loop operation?

Question

I've called some data from php using AJAX, and the result if I code alert(data.a) looks like this...

({a:[{my_id:"34", name:"Dave"}, {my_id:"39", name:"Barry"}]}

I'm not sure how to loop through this to extract the values.

My latest code...

for (var key in data.a)
{
 if (data.a.hasOwnProperty(key))
 {
   alert(key + " -> " + data.a[key]);
 }
}

... displays

0 -> [object Object]

and this displays the same too...

for (var i=0,  tot=data.a.length; i < tot; i++)
{
  for (var key in data.a[i]) 
  {
    if (data.a[i].hasOwnProperty(key))
    {
      alert(key + " -> " + data.a[i][key]);
    }
  }
}

What's the trick to looping through these results to extract the data for display?

If it helps, here's what I send at the end of my php...

$x['a'] = $myArray; 
echo json_encode($x);

Thanks for your time and help.

Alerting for debugging purpose is not recommended. Alerting an object will print [object ObjectName]. Use console.log. Your second loop is right! — Karl-André Gagnon
– Karl-André Gagnon, Commented Apr 7, 2014 at 13:10
Not able to reproduce the problem. Please check this jsfiddle.net/5xnUS — thefourtheye
– thefourtheye, Commented Apr 7, 2014 at 13:11

sWW · Accepted Answer · 2014-04-07 13:15:56Z

2

Are you after something like this? Loop through all the objects the print out all of their properties and values?

for (var i = 0; i < data.a.length; i++) {
    var objectInArray = data.a[i];
    var keys = Object.keys(objectInArray);
    for (var j = 0; j < keys.length; j++) {
        var key = keys[j];
        alert(key  + " -> " + objectInArray[key]);
    }
}

answered Apr 7, 2014 at 13:15

sWW

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Comments

Jayesh Chandrapal · Accepted Answer · 2014-04-07 13:12:02Z

1

When you are doing data.a[key] in for loop, you are getting a json object: {my_id:"34", name:"Dave"} for key = 0, and {my_id:"39", name:"Barry"} for key = 1. So in order to get values you should do something like this:

for (var key in data.a)
{
  if (data.a.hasOwnProperty(key))
  {
     alert(key + " -> " + data.a[key].my_id);
     // data.a[key].name to get name attribute
  }
}

answered Apr 7, 2014 at 13:12

Jayesh Chandrapal

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Comments

dumbledad · Accepted Answer · 2014-04-07 13:14:45Z

1

Is it just

for (var i=0; i < data.a.length; i++) {
  alert(data.a[i].my_id + " -> " + data.a[i].name);
}

answered Apr 7, 2014 at 13:14

dumbledad

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Comments

mheisig · Accepted Answer · 2014-04-07 13:23:07Z

1

In your example, data.a is an array of objects, so this would work:

for (var i = 0; i < data.a.length; i++) {
  console.log('my_id: ' + data.a[i].my_id);
  console.log('name: ' + data.a[i].name);
}

answered Apr 7, 2014 at 13:23

mheisig

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