What criteria can be used to classify PHP functions?

PHP functions can be classified according to various criteria: purpose (string processing, array processing, etc.), scope (built-in functions, user-defined functions) and return value (with return value, without return value). Practical case: The explode() function can split a string into an array with a specified delimiter.

PHP function classification criteria

PHP functions can be classified according to various criteria, the following are some common criteria:

1. Purpose

According to what the purpose of the function is, we can divide them into:

• String processing: str_replace, substr, etc.
• Array processing: array_merge, sort, etc.
• Numerical processing: round, abs, etc.
• Date and time processing: date, mktime, etc.
• File processing: fopen, fwrite, etc.

2. Scope

According to the scope of functions, we can divide them into:

• Built-in functions: Functions provided by the PHP kernel, such as echo and print.
• User-defined functions: Functions created by developers.

3. Return value

According to the return value of the function, we can divide them into:

• There is a return value: Returns a value.
• No return value: No value is returned.

Practical case:

The following is a code example that splits a string into an array:

$myString = "Lorem ipsum dolor sit amet";
$myArray = explode(" ", $myString);

print_r($myArray);

This code uses explode() Function, it splits a string into an array using spaces as delimiters. The result will be an array like this:

Array
(
    [0] => Lorem
    [1] => ipsum
    [2] => dolor
    [3] => sit
    [4] => amet
)

The above is the detailed content of What criteria can be used to classify PHP functions?. For more information, please follow other related articles on the PHP Chinese website!