PHP json_encode() Function

The JSON is a popular data format that is used to serialize and transmit structured data between the web server and application because the JSON file is human-readable and lightweight. The json_encode() is a built-in function of PHP that converts the array or object into JSON data for various purposes. The various uses of this function have shown in this tutorial.

Syntax

The first argument of this function is mandatory and the other two arguments are optional. It returns JSON data if the data is converted into JSON format properly, otherwise returns false.

string|false json_encode(mixed $value [, int $flags = 0 [, int $depth = 512]]);

The first argument contains the value that will be encoded in JSON format.

The second argument is to set the bitmask value at the time of conversion.

JSON_FORCE_OBJECT, JSON_HEX_QUOT,

JSON_HEX_TAG, JSON_HEX_AMP,

JSON_HEX_APOS, JSON_INVALID_UTF8_IGNORE,

JSON_INVALID_UTF8_SUBSTITUTE, JSON_NUMERIC_CHECK,

JSON_PARTIAL_OUTPUT_ON_ERROR, JSON_PRESERVE_ZERO_FRACTION,

JSON_PRETTY_PRINT, JSON_UNESCAPED_LINE_TERMINATORS,

JSON_UNESCAPED_SLASHES, JSON_UNESCAPED_UNICODE,

JSON_THROW_ON_ERROR.

The third argument is used to set the maximum depth that will be greater than 0.

Uses of json_encode() Function

The ways to convert different types of data into JSON format has shown in this part of the tutorial by using different examples.

Example-1: Convert PHP Array into JSON Data

Create a PHP file with the following script to know the way of converting an associative array into JSON data. An associative array of 4 elements has been declared in the script. The array values and the converted JSON values will be printed.

//Convert array to JSON data

$jsonData = json_encode($student);

//Print the JSON data

echo " The JSON values are: ". $jsonData;

?>

Output:

The following output will appear after executing the above script.

Example-2: Convert an Array into JSON Data Using JSON_NUMERIC_CHECK

Create a PHP file with the following script that will convert the array into JSON data by changing the numeric string values of the array into the numbers. The bitmask value, JSON_NUMERIC_CHECK has been used in the second argument to convert the numeric string values into the number. The array values and the converted JSON values will be printed later.

<?php

//Declare an array of different types of data

$mix_array = array('897', '4.53', 100, '-14', '2.5e3', 67, 'LinuxHint', True);

//Print the array values

echo "The array values are: ";

print_r($mix_array);

//Convert array to JSON data by checking numeric value

$jsonData = json_encode($mix_array, JSON_NUMERIC_CHECK);

//Print the JSON data

echo " The JSON values are: ". $jsonData;

?>

Output:

The following output will appear after executing the above script. In the output, four numeric string values have converted into a number and the Boolean value has converted into a number.

Example-3: Convert Array into JSON Data After Deleting the Array Value

Create a PHP file with the following script to check the way of converting array values into JSON data after deleting an element from the array. Here, an associative array of 4 elements has declared. The array has converted into JSON data before deleting any element and after deleting one element. The third element of the array has deleted in the script.

<?php

$assoc_array = array(101=>"Pen", 102=>"Pencil", 103=>"NoteBook", 104=>"Ruler");

//Print the array values

echo "The array values are: ";

print_r($assoc_array);

//Convert array to JSON data

$jsonData = json_encode($assoc_array);

//Print the JSON data

echo " The JSON values are: ". $jsonData;

unset($assoc_array[103]);

//Print the array values

echo " The array values after delete are: ";

print_r($assoc_array);

//Convert array to JSON data

$jsonData = json_encode($assoc_array);

//Print the JSON data

echo " The JSON values of the modified array are: ". $jsonData;

?>

Output:

The following output will appear after executing the above script.

Example-4: Convert a Multi-Dimensional Array into JSON Data

Create a PHP file with the following script to know the way of converting a multi-dimensional associative array into JSON data. The values of the array and converted JSON data of the array will be printed in the output.

<?php

//Declare a multi-dimensional array

$courses = array(

"department" =>"CSE",

"semester" =>2,

array(

"CSE-202" =>"C Programming",

"CSE-203" =>"Digital Logic Design",

"CSE-204" =>"Algorithm",

"Math-102"=>"Mathematics"

)

);

//Print the array values

echo "The array values are: ";

print_r($courses);

//Convert array to JSON data

$jsonData = json_encode($courses);

//Print the JSON data

echo " The JSON values are: ". $jsonData;

?>

Output:

The following output will appear after executing the above script.

Example-5: Convert an Object into JSON Data

Create a PHP file with the following script to know the way of converting an object into JSON data. A class named testClass has been defined in the script that has 3 public variables. Next, the object variable has been declared and the class variables have initialized using the object. The object properties and the converted JSON values of the object will be printed in the output.

<?php

//Declare a simple class

class testClass {

public $var1;

public $var2;

public $var3;

}

//Declare an object of the class

$object = new testClass();

//Initialize the variables of the class

$object->var1 = "Good";

$object->var2 = "Better";

$object->var3 = "Best";

//Print the object properies

echo "The object property values are: ";

print_r($object);

//Convert the object into JSON data

$jsonData = json_encode($object);

//Print the JSON data

echo " The JSON values are: ". $jsonData;

?>

Output:

The following output will appear after executing the above script.

Example-6: Convert an Array into JSON Data Using JSON_PRESERVE_ZERO_FRACTION

Create a PHP file with the following script to convert the array of fractional data into JSON data by preserving the zero-fraction value.

The bitmask value, JSON_PRESERVE_ZERO_FRACTION has been used in the second argument of the json_encode() function to preserve the zero fractional values of the array. The array values and the JSON data with zero fraction and without zero fraction will be printed in the output.

<?php

//Declare an array of numeric data

$num_array = array(78.56, 80.0, 45.09, 51.0);

//Print the array values

echo "The array values are: ";

print_r($num_array);

//Convert array to JSON data

$jsonData = json_encode($num_array);

//Print the JSON data

echo " The JSON values are: ". $jsonData;

//Convert array to JSON data by using JSON_PRESERVE_ZERO_FRACTION

$jsonData = json_encode($num_array, JSON_PRESERVE_ZERO_FRACTION);

//Print the JSON data

echo " The JSON values after preserving zero fraction are: ". $jsonData;

?>

Output:

The following output will appear after executing the above script.

Conclusion

The ways to convert array values and object properties using the json_encode() function have been explained in this tutorial by using simple examples. I hope the PHP users will be able to use this function properly after reading this tutorial.

PHP json_encode() Function

Syntax

Uses of json_encode() Function

Example-1: Convert PHP Array into JSON Data

Example-2: Convert an Array into JSON Data Using JSON_NUMERIC_CHECK

Example-3: Convert Array into JSON Data After Deleting the Array Value

Example-4: Convert a Multi-Dimensional Array into JSON Data

Example-5: Convert an Object into JSON Data

Example-6: Convert an Array into JSON Data Using JSON_PRESERVE_ZERO_FRACTION

Conclusion

About the author

Fahmida Yesmin