Using PHP's foreach to create array of values from JSON data

Question

I'm working with JSON data for the first time and I've got some PHP to grab some JSON data like below (except there are hundreds of measuregrps within body).

$json = file_get_contents("http://wbsapi.withings.net/measure?action=getmeasures");
$json_o = json_decode($json);

How do I use foreach to, say, create a 1-dimensional array of values for type = 1?

    {
        "status": 0,
        "body": {
            "updatetime": 1249409679,
            "measuregrps": [
                {
                    "grpid": 2909,
                    "attrib": 0,
                    "date": 1222930968,
                    "category": 1,
                    "measures": [
                        {
                            "value": 79300,
                            "type": 1,
                            "unit": -3
                        },
                        {
                            "value": 652,
                            "type": 5,
                            "unit": -1
                        },
                        {
                            "value": 178,
                            "type": 6,
                            "unit": -1
                        },
                        {
                            "value": 14125,
                            "type": 8,
                            "unit": -3
                        }
                    ]
                },
                {
                    "grpid": 2908,
                    "attrib": 0,
                    "date": 1222930968,
                    "category": 1,
                    "measures": [
                        {
                            "value": 78010,
                            "type": 1,
                            "unit": -3
                        }
                    ]
                },
                {
                    "grpid": 2907,
                    "attrib": 0,
                    "date": 1222930968,
                    "category": 1,
                    "measures": [
                        {
                            "value": 77300,
                            "type": 1,
                            "unit": -3
                        },
                        {
                            "value": 678,
                            "type": 5,
                            "unit": -1
                        }

                    ]
                },


            ]
        }
    }

Sometimes one's goal is clearer to the person asking than the person reading. What, exactly, should the output be? array(/* ... */) notation would be especially helpful. — Matchu
– Matchu, Commented Nov 14, 2010 at 20:01

AndreKR · Accepted Answer · 2010-11-14 20:03:54Z

2

$json_o = json_decode($json,true);

$result = array();

foreach ($json_o['body']['measuregrps'] as $measuregrp)
 foreach ($measuregrp['measures'] as $measure)
  if ($measure['type'] == 1)
   $result []= $measure['value'];

answered Nov 14, 2010 at 20:03

AndreKR

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4 Comments

AndreKR Over a year ago

But next time please try to come up with some code yourself, then we can help if it doesn't work.

Harmen Over a year ago

This actually won't work, as body etc. are instances of stdClass. They are not arrays, so they cannot be called as arrays.

PatrikAkerstrand Over a year ago

It does work, since the second parameter says that the result should use associative arrays instead of standard objects. php.net/manual/en/function.json-decode.php

JAL Over a year ago

I hate heinous mixtures of objects and arrays in PHP, so I always call JSON decode like that.

Harmen · Accepted Answer · 2010-11-14 20:10:58Z

0

Something like

$values = array();

foreach($json_o->body->measuregrps as $group){
  foreach($group->measures as $measure){
    if($measure->type == 1){
      $values[] = $measure->value;
    }
  }
}

print_r($values);

will do

edited Nov 14, 2010 at 20:10

answered Nov 14, 2010 at 20:04

Harmen

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