Focus on how to convert PHP arrays into parameters

With the continuous updating and development of Web development technology, PHP is becoming more and more widely used as a server-side programming language. Arrays are a very common and important data type when developing in PHP. Sometimes we need to convert arrays into parameters. In this article, we will focus on how to convert PHP arrays into parameters.

1. Definition of array

In PHP, arrays can be defined by two types. One is an "indexed array", which is an ordered collection of values ​​whose subscripts are natural number sequences. For example:

$arr = array('张三', '李四', '王五', '赵六');

The other is an "associative array", that is, an ordered collection of a set of values ​​whose subscript can be any string type value. For example:

$arr = array('name' => '张三', 'age' => 18, 'sex' => '男');

2. Convert the array into a string

When we need to pass the array as a parameter to the API or add it to the URL, we need to convert the array into a string form. PHP provides two functions to achieve this functionality.

1. http_build_query()

Use the http_build_query() function to convert an array into a URL query string. The syntax of this function is as follows:

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

Among them, the query_data parameter represents the array to be converted. numeric_prefixThe parameter is optional, indicating that if the array is an index array, the prefix will be added to the subscript. arg_separatorThe parameter is also optional and represents the separator between multiple parameters. enc_typeThe parameter is also optional and indicates which encoding method to use. The default is PHP_QUERY_RFC1738.

The following is a sample code that shows how to use the http_build_query() function to convert an associative array into a URL query string:

$arr = array('name' => '张三', 'age' => 18, 'sex' => '男');
$querystring = http_build_query($arr);
echo $querystring;

The output results are as follows:

name=%E5%BC%A0%E4%B8%89&age=18&sex=%E7%94%B7

2. ##implode()

In addition to using the

http_build_query() function to convert the array into a query string, we also You can use the implode() function to convert an array into a string. The syntax of this function is as follows:

string implode ( string $glue , array $pieces )

Among them, the

glue parameter represents the string used to connect the array elements, and the pieces parameter represents the array to be converted.

The following is a sample code that shows how to use the

implode() function to convert an index array into a string:

$arr = array('张三', '李四', '王五', '赵六');
$str = implode(',', $arr);
echo $str;

The output is as follows:

张三,李四,王五,赵六

3. Convert the array to JSON

If we need to convert the array into a JSON string, we can use the

json_encode() function in PHP. The syntax of this function is as follows:

string json_encode(mixed $value [, int $options = 0 [, int $depth = 512 ]])

Among them, the

value parameter represents the array to be encoded, and the options parameter is optional and can be an integer for specifying Encoding options, the depth parameter is also optional, indicating the maximum depth of encoding.

The following is a sample code that shows how to use the

json_encode() function to convert an associative array into a JSON string:

$arr = array('name' => '张三', 'age' => 18, 'sex' => '男');
$json = json_encode($arr);
echo $json;

The output is as follows:

{"name":"\u5f20\u4e09","age":18,"sex":"\u7537"}

In the output of this function, Chinese characters have been escaped into Unicode characters.

Summary

In this article, we learned how to convert a PHP array into parameters. We introduced the two functions

http_build_query() and implode(), which can convert an array into a query string or an ordinary string. We also introduced the json_encode() function, which can convert an array into a JSON string. By learning these functions, I believe you have mastered the method of converting arrays into parameters and can better perform web development work.

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