how to parse nested JSON in PHP

Question

I have this complicated JSON which I want to parse it in PHP so that I can construct dropdown.

I want to construct dropdown as

<select name="select-box">
  <option value="apple">apple</option>
    <option value="banana">banana</option>
    <option value="kiwi">kiwi</option>
</select>

Right now I'm doing something like this which is not working

$json = '[
   {
      "class":"autocomplete",
      "name":"autocomplete-1481957691348-preview",
      "value":"there is nothing like me",
      "id":"autocomplete-1481957691348-preview",
      "type":"autocomplete",
      "tag":"INPUT"
   },
   {
      "class":"form-control",
      "name":"file-1481957721195-preview",
      "value":"",
      "id":"file-1481957721195-preview",
      "type":"file",
      "tag":"INPUT"
   },
   {
      "select-box":[
         {
            "selectName":"apple",
            "optionValue":"apple"
         },
         {
            "selectName":"banana",
            "optionValue":"banana"
         },
         {
            "selectName":"kiwi",
            "optionValue":"kiwi"
         }
      ]
   },
   {
      "class":"form-control",
      "name":"select-1481957826542-preview",
      "value":"jadu",
      "id":"select-1481957826542-preview",
      "type":"select",
      "tag":"SELECT"
   }
]';

My interest is this object from above JSON

{
          "select-box":[
             {
                "selectName":"apple",
                "optionValue":"apple"
             },
             {
                "selectName":"banana",
                "optionValue":"banana"
             },
             {
                "selectName":"kiwi",
                "optionValue":"kiwi"
             }
          ]
       }

But I don't want to parse this separately. Instead I want to parse the whole JSON

$arrData    =  json_decode($json);
  echo '<select name=''>';
    foreach($arrData as $key=>$objData){
      echo '<option value='".$objData->selectName."'>'.$objData->selectName.'</option>';
    }
echo '</select>';

i need to display 2nd json shown in the code but it's structure must be like 1st json — Dilip G, Dec 17 '16 at 09:30

Ben Plummer · Answer 1 · 2016-12-17T09:36:52.923

1

You could pass true as a second parameter to json_decode to return the data as arrays rather than objects. Then you could do the following:

// Decode all of the JSON string and store into variable
$decodedJson = json_decode($json, true);

// Retrieve only the select box related data from all of the decoded JSON data
$selectOptions = $decodedJson[2]['select-box'];

echo '<select name="">';

foreach($selectOptions as $selectOption) {
    echo '<option  value="'.$selectOption['selectName'].'">'.$selectOption['selectName'].'</option>';
}

echo '</select>';

Also I've copied what you did where you have used the 'selectName' value on each option as the select box option value as well as name. Not sure if you want to change it to use the 'optionValue' value instead but I thought I'd raise it just in case.

Hope this helps!

edited Dec 17 '16 at 09:36

answered Dec 17 '16 at 09:35

Ben Plummer

449
3
9

but my json structure will change dynamically – Dilip G Dec 17 '16 at 09:36
In what sense? What issues will this cause? – Ben Plummer Dec 17 '16 at 09:38
this `$selectOptions = $decodedJson[2]['select-box'];` does not going to work for `dynamic` values – Dilip G Dec 17 '16 at 09:39
Will you always be looking for the array that contains the 'select-box' key? – Ben Plummer Dec 17 '16 at 09:41
this is not true always it will change every time . do you have any solution for this kind? – Dilip G Dec 17 '16 at 09:44
Could you give an example of how it may change please? – Ben Plummer Dec 17 '16 at 09:44
any `name` it could take instead of `select-box` like `fruit` ,`veg` and so on `dynamically` – Dilip G Dec 17 '16 at 09:46
If the 'selectName' and 'optionValue' keys always exist in these dynamically named select box arrays, they could be used to find the array, although that's not very nice. Ideally, it would be best to keep the 'select-box' name the same all the time for consistency so that it can always be easily retrieved. – Ben Plummer Dec 17 '16 at 09:51

Ionut Necula · Answer 2 · 2016-12-17T09:51:28.707

You had some mistakes in your code like:

echo '<select name=''>';

should be:

echo '<select name="">';

You can convert the object into an array and parse it like this:

<?php 
 $json = '[
   {
      "class":"autocomplete",
      "name":"autocomplete-1481957691348-preview",
      "value":"there is nothing like me",
      "id":"autocomplete-1481957691348-preview",
      "type":"autocomplete",
      "tag":"INPUT"
   },
   {
      "class":"form-control",
      "name":"file-1481957721195-preview",
      "value":"",
      "id":"file-1481957721195-preview",
      "type":"file",
      "tag":"INPUT"
   },
   {
      "select-box":[
         {
            "selectName":"apple",
            "optionValue":"apple"
         },
         {
            "selectName":"banana",
            "optionValue":"banana"
         },
         {
            "selectName":"kiwi",
            "optionValue":"kiwi"
         }
      ]
   },
   {
      "class":"form-control",
      "name":"select-1481957826542-preview",
      "value":"jadu",
      "id":"select-1481957826542-preview",
      "type":"select",
      "tag":"SELECT"
   }
]';

$arrData    =  json_decode($json, true);
  echo '<select name="">';
    foreach($arrData as $objData){
        $for_select = $objData['select-box'];
        if(is_array($for_select)){
            foreach($for_select as $sel){
                echo '<option value="'.$sel['selectName'].'">'.$sel['selectName'].'</option>';
            }
        }
    }
  echo '</select>';

Yes. But not in the OP's case. There's no need for escaping. — Ionut Necula, Dec 17 '16 at 09:50
Of course but you stated `Single quotes can't contain single quotes.` that is false if you escape them — Fabio, Dec 17 '16 at 09:51
@Fabio, yes. So I've edited my answer a little bit. I hope it helps. I know it can look like `' — Ionut Necula, Dec 17 '16 at 09:51

Fabio · Answer 3 · 2016-12-17T10:23:03.897

You have some errors with quotes and also you need to iterate in your nested json if it'not empty as follow

$arrData    =  json_decode($json);
echo '<select name="Select-box">';
foreach($arrData as $key=>$objData){
    if(!empty($objData->{'select-box'})) {
          foreach($objData->{'select-box'} as $select){

              echo '<option value="'.$select->optionValue.'">'.$select->selectName.'</option>';
          }
    }
}
echo '</select>';

//print
//<select name="select-box"><option value="apple">apple</option><option value="banana">banana</option><option value="kiwi">kiwi</option></select>

live sample

If you don't know property name because it changes all the time you can do as follow

$arrData    =  json_decode($json);
echo '<select name="select-box">';
foreach($arrData as $key=>$objData){
    foreach($objData as $data) {
        if(is_array($data)) {
             foreach($data as $select){

                  echo '<option value="'.$select->optionValue.'">'.$select->selectName.'</option>';
             }
        }
    }
}

live sample

if there is `dynamic` name for `select-box` in that scenario how can i do this. for example instead of `select-box` it is `veg` then how can i do it dynamically — Dilip G, Dec 17 '16 at 09:51

score 0 · Answer 4 · answered Dec 17 '16 at 09:44

$arrData    =  json_decode($json, TRUE);
echo '<select name="">';
foreach($arrData as $key=>$objData){
  foreach($objData['select-box'] as $key2=>$objData2){
                 echo '<option value='.$objData2['optionValue'].'>'.$objData2['selectName'].'</option>';
  }
}
echo '</select>';

how to parse nested JSON in PHP

4 Answers4