How Do Increment and Decrement Operators Work in PHP?

Symbols in PHP

Incrementing/Decrementing Operators

Increment operator
-- Decrement operator

Operation	Effect
$a	Increments $a by one, then returns $a.
$a	Returns $a, then increments $a by one.
--$a	Decrements $a by one, then returns $a.
$a--	Returns $a, then decrements $a by one.

Usage

These operators can be placed before or after the variable.

Before the variable

The increment/decrement operation is performed on the variable first, then the result is returned.

After the variable

The variable is returned first, then the increment/decrement operation is performed.

Example

$apples = 10;
for ($i = 0; $i < 10; ++$i) {
    echo 'I have ' . $apples-- . " apples. I just ate one.\n";
}

Output:

I have 10 apples. I just ate one.
I have 9 apples. I just ate one.
...
I have 1 apples. I just ate one.

Pre-increment vs. Post-increment

Pre-increment is slightly faster because it increments the variable directly, then returns the result. Post-increment creates a temporary variable and returns the original value of the variable, then increments it.

In this example, $i is used to increment the loop counter because it is more efficient.

Incrementing Letters

PHP supports incrementing letters as well:

$i = "a";
while ($i < "c") {
    echo $i++;
}

Output:

a
b

After reaching z, the next character is aa, and so on.

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