equivalent double pipe syntax to check if variable already initialized in PHP?

[johnmerlino]

Hey all,

 

Let's say I want to do something like this:

 

<?php
function exists($a){
	$b ||= $a;
}

echo exists(1);
?>

Basically, every time exists is called, it will only assign b to a if b  isn't already initialized.

 

What's the most effective way to achieve the equivalent in php? ternary?

 

Thanks for response.

[kenrbnsn]

I think what you're looking for is something like

<?php
if (!isset($b)) {
   $b = $a;
}
?>

 

Ken

[johnmerlino]

Yeah that would work.

[AbraCadaver]

Or since you brought up ternary:

 

$b = isset($b) ? $b : $a;

[johnmerlino]

Or since you brought up ternary:

 

$b = isset($b) ? $b : $a;

 

That won't work if the result is returning a function:

 

$limit = isset($this->input->get('limit')) ? $this->input->get('limit') : 25;

[AbraCadaver]

Or since you brought up ternary:

 

$b = isset($b) ? $b : $a;

 

That won't work if the result is returning a function:

 

$limit = isset($this->input->get('limit')) ? $this->input->get('limit') : 25;

 

Well no, but that wasn't their example.