php - 是否可以使用 $key 在 foreach 中创建变量？

Question

foreach ($data as $key => $value) {
    echo $key; // let say cars
}

是否可以创建一个名为的新变量$cars

Answer 1

Are you looking for extract()?

$data = array('thing' => 'ocean'
              'size' => 'big'
              'color' => 'blue');

extract($data);

echo "The $thing is $size and $color.";

Prints:

The ocean is big and blue.

---

You can use foreach and variable variables to do this:

foreach ($data as $key => $value)
{
    $$key = $value;
}

But this doesn't offer the simplicity or the options of extract() (eg: with extract(), you can add a prefix, control how you want to deal with collisions, etc.)

Answer 2

是的：$key包含"cars"，echo $$key将与：http echo $cars: //php.net/manual/en/language.variables.variable.php相同

Answer 3

是的，可以使用变量 variables，如下所示：

$key = 'cars';
$$key = 'honda'; //$cars variable is created
echo $cars; //prints 'honda'

Answer 4

I think you're asking if it's possible to create a new variable that has the same name as the value of $key - so 'cars' would create $cars, 'bikes' would create $bikes, etc?

Yes, this is possible, although it's generally not the best way to get things done.

$data = array(
    'cars' => 7,
    'bikes' => 3
);

foreach ($data as $key => $value) {
    $$key = $value;
}

echo $cars; // 7
echo $bikes; // 3

Answer 5

$key 和 $value 变量不必称为 $key 和 $value。您可以根据需要重命名变量（以及任何有效的变量名称）。

foreach($data as $cars=>$model){
    echo "$cars => $model";
}