Decode files with php

json_decode

Takes a JSON encoded string and converts it into a PHP value.

Parameters

The json string being decoded.

This function only works with UTF-8 encoded strings.

Note:

PHP implements a superset of JSON as specified in the original » RFC 7159.

When true , JSON objects will be returned as associative array s; when false , JSON objects will be returned as object s. When null , JSON objects will be returned as associative array s or object s depending on whether JSON_OBJECT_AS_ARRAY is set in the flags .

Maximum nesting depth of the structure being decoded. The value must be greater than 0 , and less than or equal to 2147483647 .

Bitmask of JSON_BIGINT_AS_STRING , JSON_INVALID_UTF8_IGNORE , JSON_INVALID_UTF8_SUBSTITUTE , JSON_OBJECT_AS_ARRAY , JSON_THROW_ON_ERROR . The behaviour of these constants is described on the JSON constants page.

Return Values

Returns the value encoded in json in appropriate PHP type. Values true , false and null are returned as true , false and null respectively. null is returned if the json cannot be decoded or if the encoded data is deeper than the nesting limit.

Errors/Exceptions

If depth is outside the allowed range, a ValueError is thrown as of PHP 8.0.0, while previously, an error of level E_WARNING was raised.

Changelog

Version	Description
7.3.0	JSON_THROW_ON_ERROR flags was added.
7.2.0	associative is nullable now.
7.2.0	JSON_INVALID_UTF8_IGNORE , and JSON_INVALID_UTF8_SUBSTITUTE flags were added.
7.1.0	An empty JSON key («») can be encoded to the empty object property instead of using a key with value _empty_ .

Examples

Example #1 json_decode() examples

var_dump ( json_decode ( $json ));
var_dump ( json_decode ( $json , true ));

The above example will output:

object(stdClass)#1 (5) < ["a"] =>int(1) ["b"] => int(2) ["c"] => int(3) ["d"] => int(4) ["e"] => int(5) > array(5) < ["a"] =>int(1) ["b"] => int(2) ["c"] => int(3) ["d"] => int(4) ["e"] => int(5) >

Example #2 Accessing invalid object properties

Accessing elements within an object that contain characters not permitted under PHP’s naming convention (e.g. the hyphen) can be accomplished by encapsulating the element name within braces and the apostrophe.

$obj = json_decode ( $json );
print $obj ->< 'foo-bar' >; // 12345

Example #3 common mistakes using json_decode()

// the following strings are valid JavaScript but not valid JSON

// the name and value must be enclosed in double quotes
// single quotes are not valid
$bad_json = «< 'bar': 'baz' >» ;
json_decode ( $bad_json ); // null

// the name must be enclosed in double quotes
$bad_json = ‘< bar: "baz" >‘ ;
json_decode ( $bad_json ); // null

// trailing commas are not allowed
$bad_json = ‘< bar: "baz", >‘ ;
json_decode ( $bad_json ); // null

Example #4 depth errors

// Encode some data with a maximum depth of 4 (array -> array -> array -> string)
$json = json_encode (
array(
1 => array(
‘English’ => array(
‘One’ ,
‘January’
),
‘French’ => array(
‘Une’ ,
‘Janvier’
)
)
)
);

// Show the errors for different depths.
var_dump ( json_decode ( $json , true , 4 ));
echo ‘Last error: ‘ , json_last_error_msg (), PHP_EOL , PHP_EOL ;

var_dump ( json_decode ( $json , true , 3 ));
echo ‘Last error: ‘ , json_last_error_msg (), PHP_EOL , PHP_EOL ;
?>

The above example will output:

array(1) < [1]=>array(2) < ["English"]=>array(2) < [0]=>string(3) "One" [1]=> string(7) "January" > ["French"]=> array(2) < [0]=>string(3) "Une" [1]=> string(7) "Janvier" > > > Last error: No error NULL Last error: Maximum stack depth exceeded

Example #5 json_decode() of large integers

var_dump ( json_decode ( $json ));
var_dump ( json_decode ( $json , false , 512 , JSON_BIGINT_AS_STRING ));

The above example will output:

object(stdClass)#1 (1) < ["number"]=>float(1.2345678901235E+19) > object(stdClass)#1 (1) < ["number"]=>string(20) "12345678901234567890" >

Notes

Note:

The JSON spec is not JavaScript, but a subset of JavaScript.

Note:

In the event of a failure to decode, json_last_error() can be used to determine the exact nature of the error.

See Also

User Contributed Notes 8 notes

JSON can be decoded to PHP arrays by using the $associative = true option. Be wary that associative arrays in PHP can be a «list» or «object» when converted to/from JSON, depending on the keys (of absence of them).

You would expect that recoding and re-encoding will always yield the same JSON string, but take this example:

$json = »;
$array = json_decode($json, true); // decode as associative hash
print json_encode($array) . PHP_EOL;

This will output a different JSON string than the original:

The object has turned into an array!

Similarly, a array that doesn’t have consecutive zero based numerical indexes, will be encoded to a JSON object instead of a list.

$array = [
‘first’,
‘second’,
‘third’,
];
print json_encode($array) . PHP_EOL;
// remove the second element
unset($array[1]);
print json_encode($array) . PHP_EOL;

The array has turned into an object!

In other words, decoding/encoding to/from PHP arrays is not always symmetrical, or might not always return what you expect!

On the other hand, decoding/encoding from/to stdClass objects (the default) is always symmetrical.

Arrays may be somewhat easier to work with/transform than objects. But especially if you need to decode, and re-encode json, it might be prudent to decode to objects and not arrays.

If you want to enforce an array to encode to a JSON list (all array keys will be discarded), use:

If you want to enforce an array to encode to a JSON object, use:

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Mastering JSON and PHP: How to Decode and Encode Files with Ease

Learn how to decode and encode JSON files in PHP with ease. Our guide covers everything from converting to accessing data and best practices for working with JSON in PHP. Get started today!

• Introduction
• Converting JSON to PHP Arrays
• How to encode and decode JSON data using PHP
• Encoding and Decoding JSON Data
• Accessing Data from JSON in PHP
• Important Points about JSON and PHP
• Helpful Points
• Other PHP code samples for decoding JSON files
• Conclusion
• How to decode a JSON file in PHP?
• How to read JSON data from file in PHP?
• How to decode JSON response in PHP?
• How to convert JSON file into array PHP?

JSON (JavaScript Object Notation) is a lightweight data interchange format that is widely used in web applications. It is easy to read and write, and it has become a popular choice for data exchange between servers and web applications. PHP is a powerful server-side scripting language that is widely used for web development. In this article, we will learn how to parse and decode JSON files using PHP.

Introduction

JSON is a popular data format that is used to exchange data between servers and web applications. It is based on a subset of the JavaScript programming language and is easy to read and write. JSON is lightweight and has become a popular choice for data exchange between servers and web applications.

In this article, we will focus on how to decode and encode JSON files using PHP. We will cover the basics of JSON and PHP, and we will provide examples of how to use PHP to parse and decode JSON data.

Converting JSON to PHP Arrays

JSON data can be easily converted to a PHP array using the json_decode() function. The json_decode() function takes a JSON string as input and returns a PHP array.

To convert a JSON file to a PHP array, we can use the following code:

$json_data = file_get_contents('data.json'); $php_array = json_decode($json_data, true); 

In this code, we first read the contents of the data.json file using the file_get_contents() function. The contents of the file are then passed to the json_decode() function, which returns a PHP array.

By default, the json_decode() function returns an object. If we want to get an associative array instead, we can pass true as the second parameter to the json_decode() function.

$json_data = ''; $php_array = json_decode($json_data, true); 

In this example, we create a JSON string manually and pass it to the json_decode() function. The resulting PHP array is:

Array ( [name] => John [age] => 30 [city] => New York ) 

How to encode and decode JSON data using PHP

JSON data are everywhere. In this video we are going to learn how to encode and decode php Duration: 7:02

Encoding and Decoding JSON Data

Encoding data into JSON format is also easy using the json_encode() function. The json_encode() function takes a PHP array as input and returns a JSON string.

$php_array = array("name"=>"John", "age"=>30, "city"=>"New York"); $json_data = json_encode($php_array); 

In this example, we create a PHP array and pass it to the json_encode() function. The resulting JSON string is:

To decode a JSON data string into a PHP array, we can use the json_decode() function.

$json_data = ''; $php_array = json_decode($json_data, true); 

Accessing Data from JSON in PHP

Once we have a PHP array that contains JSON data, we can easily access individual elements using array notation.

$json_data = ''; $php_array = json_decode($json_data, true); echo $php_array['name']; // Output: John echo $php_array['age']; // Output: 30 echo $php_array['city']; // Output: New York 

We can also use the file_get_contents() function to read the contents of a JSON file into a variable.

$json_data = file_get_contents('data.json'); $php_array = json_decode($json_data, true); 

Important Points about JSON and PHP

Working with JSON and PHP requires a basic understanding of both technologies. Here are some important points to keep in mind:

• PHP has standard functions available for generating, parsing, and interpreting JSON format.
• JSON data is easy to read and write, and it is lightweight.
• JSON data can be used to exchange data between servers and web applications.
• JSON data can be easily converted to a PHP array using the json_decode() function.
• PHP arrays can be easily converted to JSON data using the json_encode() function.
• When decoding JSON data, make sure to check for errors using the json_last_error() function.

Helpful Points

• Always validate JSON data before parsing it.
• Use the json_last_error() function to handle errors during encoding and decoding.
• Use the $associative = true option to decode JSON data into associative arrays.
• Avoid using json_decode() on untrusted data.
• Use a JSON validator to validate your JSON data before parsing it.

Other PHP code samples for decoding JSON files

$json = json_decode(file_get_contents('/path/to/your/file.json'));

In Php as proof, php decode json object code example

';$personInfo = json_decode(json);echo $personInfo->age;?>

In Php case in point, php try to decode json code sample

/** Checks if JSON and returns decoded as an array, if not, returns false, but you can pass the second parameter true, if you need to return a string in case it's not JSON */ function tryJsonDecode($string, $returnString = false) < $arr = json_decode($string); if (json_last_error() === JSON_ERROR_NONE) < return $arr; >else < return ($returnString) ? $string : false; >>

In Php , for instance, php json decode code example

Conclusion

JSON is a popular data format that is used to exchange data between servers and web applications. In this article, we learned how to parse and decode JSON files using PHP. We covered the basics of JSON and PHP, and we provided examples of how to use PHP to parse and decode JSON data.

By following the best practices and tips outlined in this article, you can become proficient in working with JSON data in PHP. With the ability to decode and encode JSON data, you will have a powerful tool at your disposal for exchanging data between servers and web applications.

Frequently Asked Questions — FAQs

What is JSON and why is it important for software development?

JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is important for software development as it allows for the easy exchange of data between different programming languages and systems.

How do I convert a JSON file into a PHP array?

You can use the json_decode() function to convert a JSON file into a PHP array. This function takes two parameters: the JSON data and a Boolean value that specifies whether to return the data as an associative array.

How do I encode data into JSON format in PHP?

You can use the json_encode() function to encode data into JSON format. This function takes one parameter: the data to be encoded.

What are some common issues when working with JSON in PHP?

One common issue is invalid JSON syntax, which can cause errors when decoding JSON data. Another issue is encoding/decoding errors, which can occur when the data is not in the correct format.

What are some best practices for working with JSON in PHP?

Some best practices include validating JSON data before decoding it, using associative arrays when decoding JSON data, and using proper error handling techniques.

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