How to convert key-value string in php array

PHP is a very popular server-side scripting language with powerful data processing capabilities. In PHP, an array is a very commonly used data type that can store multiple values ​​and be accessed using either a numeric index or a string index. In this article, we will explain how to convert a PHP array into a key-value string.

1. Use the implode function

The implode function can connect the elements in the array in the form of a string. Its syntax is as follows:

string implode ( string $glue , array $pieces )

$glue is the string used to connect array elements, $pieces is the array to be connected.

If we want to convert an array of key-value pairs into a key-value string, we can follow the following steps:

$my_array = array("key1" => "value1", "key2 " => "value2", "key3" => "value3");
$key_value_string = implode("&", array_map(function ($k, $v) { return $k.'='. $v; }, array_keys($my_array), $my_array));

This code concatenates the array $my_array into a key-value string with "&" as the separator. Among them, the array_map function splices each key-value pair, and the array_keys function returns all the key names of the array. The output result is:

key1=value1&key2=value2&key3=value3

2. Use the http_build_query function

http_build_query function to convert the associative array into a URL-encoded query string. The syntax is as follows:

string http_build_query ( mixed $query_data [, string $numeric_prefix [, string $arg_separator [, int $enc_type = PHP_QUERY_RFC1738 ]]] )

$query_data is the association to be converted Array, $numeric_prefix is ​​an optional numeric prefix (default is null), $arg_separator is an optional parameter separator (default is &), $enc_type is the URL encoding type (default is PHP_QUERY_RFC1738).

If we want to convert an array of key-value pairs into a key-value string, we can follow the following steps:

$my_array = array("key1" => "value1", "key2 " => "value2", "key3" => "value3");
$key_value_string = http_build_query($my_array);

This code converts the array $my_array into a key-value character string. The output result is:

key1=value1&key2=value2&key3=value3

3. Use foreach loop

If you don’t want to use a function, you can also use foreach loop to convert the key-value pair array is a key-value string. The sample code is as follows:

$my_array = array("key1" => "value1", "key2" => "value2", "key3" => "value3" );
$key_value_string = "";
foreach ($my_array as $key => $value) {

$key_value_string .= urlencode($key).'='.urlencode($value).'&';

}
$key_value_string = rtrim($key_value_string, '&' );

This code also converts the array $my_array into a key-value string with "&" as the delimiter. The urlencorde function is used to URL encode special characters. The output result is the same as method 1 and method 2.

Summary

The above three methods can convert PHP arrays into key-value strings. Methods 1 and 2 use built-in functions and are more efficient. Method 3 uses a foreach loop, which requires a large amount of code. Just choose according to actual needs. In addition, if you need to convert the key value string into an array, you can use the parse_str function for parsing.

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