{"id":2261,"date":"2021-07-11T02:02:52","date_gmt":"2021-07-11T02:02:52","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=2261"},"modified":"2025-04-06T02:45:41","modified_gmt":"2025-04-06T02:45:41","slug":"php-variadic-functions","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-tutorial\/php-variadic-functions\/","title":{"rendered":"PHP Variadic Functions"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn about the PHP variadic functions that accept a variable number of arguments.<\/p>\n\n\n\n

Introduction to the PHP variadic functions #<\/a><\/h2>\n\n\n\n

So far, you’ve learned how to define functions<\/a> that accept a fixed number of parameters<\/a>. A variadic function accepts a variable number of parameters.<\/p>\n\n\n\n

The following example defines a function called sum()<\/code> that returns the sum of two integers:<\/p>\n\n\n

<?php<\/span>\n\nfunction<\/span> sum<\/span>(int $x, int $y)<\/span>\n<\/span>{\n    return<\/span> $x + $y;\n}\n\necho<\/span> sum(10<\/span>, 20<\/span>); \/\/ 30<\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
To allow the sum()<\/code> function to accept a variable of arguments, you need to use func_get_args()<\/code> function. The func_num_args()<\/code> function returns an array<\/a> that contains all function arguments. For example:<\/p>\n\n\n
<?php<\/span>\n\nfunction<\/span> sum<\/span>()<\/span>\n<\/span>{\n    $numbers = func_get_args();\n    $total = 0<\/span>;\n    for<\/span> ($i = 0<\/span>; $i < count($numbers); $i++) {\n        $total += $numbers[$i];\n    }\n\n    return<\/span> $total;\n}\necho<\/span> sum(10<\/span>, 20<\/span>) . '<br>'<\/span>; \/\/ 30<\/span>\necho<\/span> sum(10<\/span>, 20<\/span>, 30<\/span>) . '<br>'<\/span>; \/\/ 60<\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, we don’t specify any parameter for the sum()<\/code> function. When calling the sum()<\/code> function, we can pass any number of arguments into it.<\/p>\n\n\n\n
Inside the function, the func_get_args()<\/code> returns an array that contains all the arguments. To sum up all the arguments, we use a for<\/a><\/code> loop.<\/p>\n\n\n\n
PHP 5.6 introduced the ...<\/code> operator. When you place the ...<\/code> operator in front of a function parameter, the function will accept a variable number of arguments, and the parameter will become an array inside the function. For example:<\/p>\n\n\n
<?php<\/span>\n\nfunction<\/span> sum<\/span>(...$numbers)<\/span>\n<\/span>{\n    $total = 0<\/span>;\n    for<\/span> ($i = 0<\/span>; $i < count($numbers); $i++) {\n        $total += $numbers[$i];\n    }\n\n    return<\/span> $total;\n}\necho<\/span> sum(10<\/span>, 20<\/span>) . '<br>'<\/span>; \/\/ 30<\/span>\necho<\/span> sum(10<\/span>, 20<\/span>, 30<\/span>) . '<br>'<\/span>; \/\/ 60<\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, we place the ...<\/code> operator in front of the $numbers<\/code> argument. The sum()<\/code> function now accepts a variable of number arguments.<\/p>\n\n\n\n
PHP 7 allows you to declare types for variadic arguments. For example:<\/p>\n\n\n
<?php<\/span>\n\nfunction<\/span> sum<\/span>(int ...$numbers)<\/span>: int<\/span>\n<\/span>{\n    $total = 0<\/span>;\n    for<\/span> ($i = 0<\/span>; $i < count($numbers); $i++) {\n        $total += $numbers[$i];\n    }\n\n    return<\/span> $total;\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, the sum()<\/code> function will accept only integers and return the sum of integers.<\/p>\n\n\n\n
If a function has multiple parameters, only the last parameter can be variadic. For example:<\/p>\n\n\n
function<\/span> my_func<\/span>($a, $b, ...$params)<\/span> <\/span>{\n    \/\/ ...<\/span>\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
If you place the variadic parameter before a regular one, you’ll get an error:<\/p>\n\n\n
Fatal error: Only the last parameter can be variadic in...<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
A function only has one variadic parameter.<\/p>\n\n\n\n
Note that you can use the array_sum()<\/code> to calculate the sum of all elements of an array. So you can simplify the sum()<\/code> function like this:<\/p>\n\n\n
<?php<\/span>\n\nfunction<\/span> sum<\/span>(int ...$numbers)<\/span>: int<\/span>\n<\/span>{\n    return<\/span> array_sum($numbers);\n}<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Summary #<\/a><\/h2>\n\n\n\n
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  • A variadic function accepts a variable number of arguments.<\/li>\n\n\n\n
  • Do use the ...<\/code> operator to define a variadic function.<\/li>\n\n\n\n
  • Only the last parameter can be variadic.<\/li>\n<\/ul>\n
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