php function to convert array

PHP is a widely used server-side scripting language commonly used for website development. During development, manipulating arrays is very common. Sometimes we need to convert some data into an array. PHP provides a variety of functions to achieve this function. The following is an introduction to the PHP array conversion function.

1. json_decode function

json_decode function is used to convert JSON format strings into PHP arrays. JSON is a lightweight data exchange format commonly used for front-end and back-end data transmission. It is very convenient to use this function. You only need to pass in the JSON format string as a parameter.

Sample code:

$json_str = '{"name": "Tom", "age": 20}';
$array = json_decode($json_str, true);
print_r($array);

Output:

Array
(
    [name] => Tom
    [age] => 20
)

It should be noted that the JSON format string accepted by the json_decode function must be legal, otherwise NULL will be returned. In addition, this function has a second parameter, indicating whether to convert the JSON object into a PHP object instead of an array. true means converting to an array, false means converting to an object, and the default is false.

2. explode function

The explode function is used to split a string into an array according to the specified delimiter. This function is very convenient when processing text files such as CSV files.

Sample code:

$str = "apple,banana,orange";
$array = explode(",", $str);
print_r($array);

Output:

Array
(
    [0] => apple
    [1] => banana
    [2] => orange
)

3. preg_split function

The preg_split function is a more flexible string Split function, you can use regular expressions to specify the delimiter. Compared with the explode function, this function can handle more complex string splitting.

Sample code:

$str = "Hello     World";
$array = preg_split('/\s+/', $str);
print_r($array);

Output:

Array
(
    [0] => Hello
    [1] => World
)

It should be noted that the first parameter of the preg_split function is a regular expression used to match the delimiter.

4. str_split function

The str_split function is used to split a string into an array of single characters. This function is very useful in some string processing.

Sample code:

$str = "Hello World";
$array = str_split($str);
print_r($array);

Output:

Array
(
    [0] => H
    [1] => e
    [2] => l
    [3] => l
    [4] => o
    [5] =>  
    [6] => W
    [7] => o
    [8] => r
    [9] => l
    [10] => d
)

5. array_map function

array_map function is a method for each element in an array A function that performs specific operations on elements. It can pass all elements in one or more arrays to a user-defined function for processing. Use this function to easily convert arrays.

Sample code:

$array = array(1, 2, 3, 4);
$new_array = array_map(function($i) {
    return $i * $i;
}, $array);
print_r($new_array);

Output:

Array
(
    [0] => 1
    [1] => 4
    [2] => 9
    [3] => 16
)

It should be noted that the array_map function returns a new array after execution, and the original array has not changed.

The above are the commonly used array conversion functions in PHP. Using these functions can easily convert some data into arrays for subsequent operations. Of course, there are other array operation functions in PHP, and you need to choose the appropriate function according to the actual situation.

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