PHP 8 Union types
Last Updated :
27 Jul, 2021
A “union type” accepts values of multiple different data types, rather than a single one. If the programming language supports union types, you can declare a variable in multiple types. For example, there can be a function that can accept the variable of type “string” or “float” as a parameter. PHP already supports two special union types.
- Type or null, using the special “?Type” syntax.
- Array or Traversable, using the special iterable type.
But before the update, arbitrary union types were not supported by the language. Instead, we used PHPDoc annotations which was quite a work to do.
Example 1:
PHP
<?php
class GFG {
private $CodingScore;
public function setScore($CodingScore) {
$this->CodingScore = $CodingScore;
}
public function getScore() {
return $this->CodingScore;
}
}
$a = new GFG();
$a->setScore(120.5);
echo $a->getScore(), "\r\n" ;
$b = new GFG();
$b->setScore(100);
echo $b->getScore();
?>
|
Output:
120.5
100
But after this update, Union types are specified using the following syntax
T1|T2|...
It can be used in all positions where types are currently accepted as follows.
Example 2:
PHP
<?php
class GFG {
private int|float $CodingScore;
public function setScore(int|float $CodingScore): void {
$this->CodingScore = $CodingScore;
}
public function getScore(): int|float {
return $this->CodingScore;
}
}
$a = new GFG();
$a->setScore(120.8);
echo $a->getScore(),"\r\n";
$a->setScore(100);
echo $a->getScore();
?>
|
Output:
120.8
100
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