How to Convert Positive Numbers to Negative in PHP?

In PHP, you can convert a positive number to negative in the following ways:

If you wish to always return a negative number (i.e. retain the sign of a negative number whilst ensuring that any positive number is converted to negative), then you can first convert the number to its absolute form, and then negate it.

#Using Negation Operator

You can convert a positive number to negative by using the negation operator (-) like so:

-n

For example, you can use this in the following way:

$num = 1234;
$negated = -$num;

var_dump($negated); // -1234

#Using Arithmetic Operators

You can convert a positive number to negative by simply multiplying or dividing it by -1:

n * -1
n / -1

Alternatively, you may subtract the number from 0:

0 - n

You can use any of these to convert a positive number to a negative number, for example, like so:

$num = 1234;
$negated = $num * -1;

var_dump($negated); // -1234
$num = 1234;
$negated = $num / -1;

var_dump($negated); // -1234
$num = 1234;
$negated = 0 - $num;

var_dump($negated); // -1234

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