How do I extract data from JSON with PHP

Question

This is intended to be a general reference question and answer covering many of the never-ending  How do I access data in my JSON   questions  It is here to handle the broad basics of decoding JSON in PHP and accessing the results    I have the JSON          type    donut        name    Cake        toppings                id    5002    type    Glazed                id    5006    type    Chocolate with Sprinkles                id    5004    type    Maple              How do I decode this in PHP and access the resulting data

User · Answer

The acepted Answer is very detailed and correct in most of the cases.

I just want to add that i was getting an error while attempting to load a JSON text file encoded with UTF8, i had a well formatted JSON but the 'json_decode' always returned me with NULL, it was due the BOM mark.

To solve it, i made this PHP function:

function load_utf8_file($filePath)
{
    $response = null;
    try
    {
        if (file_exists($filePath)) {
            $text = file_get_contents($filePath);
            $response = preg_replace("/^\xEF\xBB\xBF/", '', $text);          
        }     
    } catch (Exception $e) {
      echo 'ERROR: ',  $e->getMessage(), "\n";
   }
   finally{  }
   return $response;
}

Then i use it like this to load a JSON file and get a value from it:

$str = load_utf8_file('appconfig.json'); 
$json = json_decode($str, true); 
//print_r($json);
echo $json['prod']['deploy']['hostname'];

User · Answer

Intro  First off you have a string  JSON is not an array  an object  or a data structure  JSON is a text-based serialization format - so a fancy string  but still just a string  Decode it in PHP by using json decode       data   json decode  json     Therein you might find    scalars  strings  ints  floats  and bools nulls  a special type of its own  compound types  objects and arrays    These are the things that can be encoded in JSON  Or more accurately  these are PHP s versions of the things that can be encoded in JSON   There s nothing special about them  They are not  JSON objects  or  JSON arrays   You ve decoded the JSON - you now have basic everyday PHP types   Objects will be instances of stdClass  a built-in class which is just a generic thing that s not important here     Accessing object properties  You access the properties of one of these objects the same way you would for the public non-static properties of any other object  e g   object- gt property    json            type    donut        name    Cake        yummy   json decode  json    echo  yummy- gt type    donut     Accessing array elements  You access the elements of one of these arrays the same way you would for any other array  e g   array 0     json            Glazed        Chocolate with Sprinkles        Maple        toppings   json decode  json    echo  toppings 1     Chocolate with Sprinkles   Iterate over it with foreach   foreach   toppings as  topping        echo  topping    n          Glazed    Chocolate with Sprinkles    Maple   Or mess about with any of the bazillion built-in array functions     Accessing nested items  The properties of objects and the elements of arrays might be more objects and or arrays - you can simply continue to access their properties and members as usual  e g   object- gt array 0 - gt etc    json            type    donut        name    Cake        toppings                id    5002    type    Glazed                id    5006    type    Chocolate with Sprinkles                id    5004    type    Maple                yummy   json decode  json    echo  yummy- gt toppings 2 - gt id    5004     Passing true as the second argument to json decode    When you do this  instead of objects you ll get associative arrays - arrays with strings for keys  Again you access the elements thereof as usual  e g   array  key      json            type    donut        name    Cake        toppings                id    5002    type    Glazed                id    5006    type    Chocolate with Sprinkles                id    5004    type    Maple                yummy   json decode  json  true    echo  yummy  toppings   2   type      Maple     Accessing associative array items  When decoding a JSON object to an associative PHP array  you can iterate both keys and values using the foreach  array expression as  key   gt   value  syntax  eg   json            foo    foo value        bar    bar value        baz    baz value        assoc   json decode  json  true   foreach   assoc as  key   gt   value        echo  The value of key   key  is   value    PHP EOL      Prints     The value of key  foo  is  foo value    The value of key  bar  is  bar value    The value of key  baz  is  baz value      Don t know how the data is structured  Read the documentation for whatever it is you re getting the JSON from   Look at the JSON - where you see curly brackets    expect an object  where you see square brackets    expect an array   Hit the decoded data with a print r      json            type    donut        name    Cake        toppings                id    5002    type    Glazed                id    5006    type    Chocolate with Sprinkles                id    5004    type    Maple                yummy   json decode  json    print r  yummy     and check the output   stdClass Object        type    gt  donut      name    gt  Cake      toppings    gt  Array                        0    gt  stdClass Object                                        id    gt  5002                      type    gt  Glazed                                 1    gt  stdClass Object                                        id    gt  5006                      type    gt  Chocolate with Sprinkles                                 2    gt  stdClass Object                                        id    gt  5004                      type    gt  Maple                                   It ll tell you where you have objects  where you have arrays  along with the names and values of their members   If you can only get so far into it before you get lost - go that far and hit that with print r     print r  yummy- gt toppings 0        stdClass Object        id    gt  5002      type    gt  Glazed     Take a look at it in this handy interactive JSON explorer   Break the problem down into pieces that are easier to wrap your head around     json decode   returns null  This happens because either    The JSON consists entirely of just that  null  The JSON is invalid - check the result of json last error msg or put it through something like JSONLint  It contains elements nested more than 512 levels deep  This default max depth can be overridden by passing an integer as the third argument to json decode      If you need to change the max depth you re probably solving the wrong problem  Find out why you re getting such deeply nested data  e g  the service you re querying that s generating the JSON has a bug  and get that to not happen     Object property name contains a special character  Sometimes you ll have an object property name that contains something like a hyphen - or at sign   which can t be used in a literal identifier  Instead you can use a string literal within curly braces to address it    json       attributes    answer  42      thing   json decode  json    echo  thing- gt    attributes  - gt answer    42   If you have an integer as property see  How to access object properties with names like integers  as reference     Someone put JSON in your JSON  It s ridiculous but it happens - there s JSON encoded as a string within your JSON  Decode  access the string as usual  decode that  and eventually get to what you need    json            type    donut        name    Cake        toppings         type      Glazed          type      Maple             yummy   json decode  json    toppings   json decode  yummy- gt toppings    echo  toppings 0 - gt type    Glazed     Data doesn t fit in memory  If your JSON is too large for json decode   to handle at once things start to get tricky  See    Processing large JSON files in PHP How to properly iterate through a big json file     How to sort it  See  Reference  all basic ways to sort arrays and data in PHP

User · Answer

You can use json decode   to convert a json string to a PHP object array   Eg   Input    json      a  1  b  2  c  3  d  4  e  5     var dump json decode  json    var dump json decode  json  true      Output   object stdClass  1  5          a     gt  int 1        b     gt  int 2        c     gt  int 3        d     gt  int 4        e     gt  int 5     array 5          a     gt  int 1        b     gt  int 2        c     gt  int 3        d     gt  int 4        e     gt  int 5      Few Points to remember    json decode requires the string to be a valid json else it will return NULL  In the event of a failure to decode  json last error   can be used to determine the exact nature of the error  Make sure you pass in utf8 content  or json decode may error out and just return a NULL value

User · Answer

Using json as php array    json       user id   1   user name   Sayeed Amin   time   2019-11-06 13 21 26         or use from file    json   file get contents  results json      someArray   json decode  json  true    foreach   someArray as  key   gt   value        echo  value  user id             value  user name             value  time       lt br gt

User · Answer

https   paiza io projects X1QjjBkA8mDo6oVh-J 63w  Check below code for converting json to array in PHP  If JSON is correct then json decode   works well  and will return an array  But if malformed JSON  then It will return NULL    lt  php function jsonDecode1  json        arr   json decode  json  true       return  arr        In case of malformed JSON  it will return NULL var dump  jsonDecode1  json       If malformed JSON  and you are expecting only array  then you can use this function    lt  php function jsonDecode2  json        arr    array  json decode  json  true       return  arr        In case of malformed JSON  it will return an empty array   var dump  jsonDecode2  json       If malformed JSON  and you want to stop code execution  then you can use this function    lt  php function jsonDecode3  json        arr    array  json decode  json  true        if empty json last error              return  arr            else          throw new ErrorException  json last error msg                  In case of malformed JSON  Fatal error will be generated var dump  jsonDecode3  json       You can use any function depends on your requirement

User · Answer

Consider using JSONPath https   packagist org packages flow jsonpath  There is a pretty clear explanation of how to use it and parse a JSON-file avoiding all the loops proposed  If you are familiar with XPath for XML you will start loving this approach

User · Answer

We can decode json string into array using json decode function in php  1  json decode  json string     it returns object  2  json decode  json string true     it returns array   json string           type    donut        name    Cake        toppings                id    5002    type    Glazed                id    5006    type    Chocolate with Sprinkles                id    5004    type    Maple               array   json decode  json string true    echo  array  type      it gives donut

[php] How do I extract data from JSON with PHP?

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