PHP通过JSON循环以创建新数组

Question

I am not sure why I am having such a hard time with this but I have some Decoded JSON and I want to loop through it to build a smaller array using some of the data.

Below is my JSON $jsonData :

{
  "resultsPage": {
    "results": {
      "event": [
        {
          "id":11129128,
          "type":"Concert",
          "uri":"http://www.songkick.com/concerts/11129128-wild-flag-at-fillmore?utm_source=PARTNER_ID&utm_medium=partner",
          "displayName":"Wild Flag at The Fillmore (April 18, 2012)",
          "start": {
            "time":"20:00:00",
            "date":"2012-04-18",
            "datetime":"2012-04-18T20:00:00-0800"
          },
       location": {
            "city":"Chicago, IL, US",
            "lng":-134.903409,
            "lat":37.7842398
          },
          "venue": {
            "id":6239,
            "displayName":"The Fillmore",
            "uri":"http://www.songkick.com/venues/6239-fillmore?utm_source=PARTNER_ID&utm_medium=partner",
            "lng":-122.4332937,
            "lat":37.7842398,
            "metroArea": {
              "id":26330,
              "uri":"http://www.songkick.com/metro_areas/26330-us-sf-bay-area?utm_source=PARTNER_ID&utm_medium=partner",
              "displayName":"SF Bay Area",
              "country": { "displayName":"US" },
              "state": { "displayName":"CA" }
            }
          },
          "status":"ok",
          "popularity":0.012763
        },
        {
          "id":7923094,
          "type":"Concert",
          "uri":"http://www.songkick.com/concerts/11129128-wild-flag-at-fillmore?utm_source=PARTNER_ID&utm_medium=partner",
          "displayName":"Wild Flag at The Fillmore (April 18, 2012)",
          "start": {
            "time":"20:00:00",
            "date":"2012-04-18",
            "datetime":"2012-04-18T20:00:00-0800"
          },
       location": {
            "city":"New York, NY, US",
            "lng":63.902374,
            "lat":49.7842328
          },
          "venue": {
            "id":6239,
            "displayName":"The Fillmore",
            "uri":"http://www.songkick.com/venues/6239-fillmore?utm_source=PARTNER_ID&utm_medium=partner",
            "lng":-122.4332937,
            "lat":37.7842398,
            "metroArea": {
              "id":26330,
              "uri":"http://www.songkick.com/metro_areas/26330-us-sf-bay-area?utm_source=PARTNER_ID&utm_medium=partner",
              "displayName":"SF Bay Area",
              "country": { "displayName":"US" },
              "state": { "displayName":"CA" }
            }
          },
          "status":"ok",
          "popularity":0.012763
        },

        {
          "id":89763146,
          "type":"Concert",
          "uri":"http://www.songkick.com/concerts/11129128-wild-flag-at-fillmore?utm_source=PARTNER_ID&utm_medium=partner",
          "displayName":"Wild Flag at The Fillmore (April 18, 2012)",
          "start": {
            "time":"20:00:00",
            "date":"2012-04-18",
            "datetime":"2012-04-18T20:00:00-0800"
          },
       location": {
            "city":"Miami, FL, US",
            "lng":42.1238243,
            "lat":50.7289731
          },
          "venue": {
            "id":6239,
            "displayName":"The Fillmore",
            "uri":"http://www.songkick.com/venues/6239-fillmore?utm_source=PARTNER_ID&utm_medium=partner",
            "lng":-122.4332937,
            "lat":37.7842398,
            "metroArea": {
              "id":26330,
              "uri":"http://www.songkick.com/metro_areas/26330-us-sf-bay-area?utm_source=PARTNER_ID&utm_medium=partner",
              "displayName":"SF Bay Area",
              "country": { "displayName":"US" },
              "state": { "displayName":"CA" }
            }
          },
          "status":"ok",
          "popularity":0.012763
        }
      ]
    },
    "totalEntries":24,
    "perPage":50,
    "page":1,
    "status":"ok"
  }
}

Below is my first try at looping through the JSON variable and parsing out the data I want into a new array. I am not sure if I should use push or if there is a more effiecent way to parse the data I want into a new array:

$newArray = array();

foreach($jsonData['resultsPage']['results']['event'] as $val){

$newArray .= "{'id' => $val['id'], 'long' => $val['location']['lng'], 'lat' => $val['location']['lat']}"

}

Answer 1

Try this:

$jsondata_array = json_decode($jsonData, true);

$new_required_arr = $jsondata_array['resultsPage']['results']['event'];

foreach($new_required_arr as $key => $val)
{
  //Your logic to create new array with required key value pair.
}

Answer 2

The provided JSON format is wrong, the index location missing the double quote at the beginning.

To parse the JSON , you can convert JSON to array and loop through the array to apply your logic OR build new array, you can use json_decode with true parameter.

$arr = json_decode($json, true);
foreach($arr as $k => $v){
  //Your logic
}

Answer 3

The problem with you loop is when the element don't exist you get an error because you try to access an element in your array which doesn't exist.

foreach($jsonData as $val) {
}

Then you can work insight with your values and you should check them with isset . Or you make an if statement around your loop to prevent it that problem.

The next problem is that you define $newArray as an array. But the . is to concat a string. So you should define your initial variable like this:

$newArray = '';

The last thing is i can't see it in your code but to parse a json string you have to use json_decode first. To get an object. If you want an array you have to set the second parameter to true .

$arr = json_decode($myjson, true);