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How to output an array using php native writing method

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Release： 2023-05-07 11:33:07

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In PHP, array is a very important data type. In many scenarios, we need to output an array to the browser or console for debugging or data display. This article will introduce PHP's native writing method to output arrays. The following will be introduced from two aspects: the first is to print the array, and the second is to convert the array into JSON format.

1. Print array

Print an array directly. PHP’s default output method is to convert it into a string and then output it. However, when there are many array elements or the array structure is complex, this output method may cause the output information to not be clearly displayed. In this case, we can use the print_r() function or var_dump() function provided by PHP to output the array, as shown below:

Use the print_r() function

## The #print_r() function accepts an array as a parameter and outputs the structure and element values of the array. The element values are based on the key-value correspondence of the array and will be automatically indented when output, as shown below:

<?php
  $arr = array(
    "name" => "Kevin",
    "age" => 30,
    "gender" => "male"
  );
  print_r($arr);
?>

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The print result is as follows:

Array
(
    [name] => Kevin
    [age] => 30
    [gender] => male
)

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The var_dump() function also accepts an array as a parameter, but unlike print_r(), var_dump( ) function will output the type and value of the parameter, along with more detailed information, such as data type and number of elements. When printing the array, each element will be output in the form of the corresponding "[key] => [value]" , as shown below:

<?php
  $arr = array(
    "name" => "Kevin",
    "age" => 30,
    "gender" => "male"
  );
  var_dump($arr);
?>

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The printing result is as follows:

array(3) {
  ["name"]=>
  string(5) "Kevin"
  ["age"]=>
  int(30)
  ["gender"]=>
  string(4) "male"
}

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2. Convert the array into JSON format

JSON (JavaScript Object Notation) is a lightweight The data exchange format uses key-value pairs to represent data, which is highly readable and easy to parse and generate. In web development, the JSON format has become a very popular data exchange format. Therefore, we usually need to convert a PHP array into JSON format so that the web front end can read it and parse and process it accordingly.

Using the json_encode() function that comes with PHP, we can convert an array into a string in JSON format. This function accepts an array as a parameter and returns a string in JSON format corresponding to the array. As shown below:

<?php
  $arr = array(
    "name" => "Kevin",
    "age" => 30,
    "gender" => "male"
  );
  echo json_encode($arr);
?>

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The printed result is as follows:

{"name":"Kevin","age":30,"gender":"male"}

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It should be noted that the json_encode() function can only convert UTF-8 encoded strings into JSON format, so when using this function, you need to ensure that the elements of the array are UTF-8 encoded strings. If the array elements contain other types, such as integers or objects, the json_encode() function will automatically convert them into the corresponding JSON format.

To sum up, this article introduces the native writing method of PHP to output arrays and convert arrays into JSON format. Hope this helps with using PHP arrays.

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