asked on

Why did I first need to declare this variable in PHP?

Please see the following code: the commented line below marks the variable PHP demanded I declare, but I use variables all the time without declaring them first. Why did PHP throw an error? I knew the remedy but wanted to expand my understanding. Thanks.

<?php

$selected_car = "chevy";

$car_choices = array ("ford", "chevy", "dodge");

//without declaring this variable I get an error?
$options = "";


foreach ($car_choices as $car_choice) {
	
	$selected = ($selected_car == $car_choice) ? "selected"	: "";
	$options .= "<option $selected % {$car_choice}>{$car_choice}</option>";
	
}


?>

<select>

<?php echo $options ?>

</select>

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SOLUTION

Ray Paseur

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ASKER CERTIFIED SOLUTION

Radek Baranowski

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LB1234

ASKER

This may sound really dumb, but aren't I defining it at line 14? How is what I'm doing on line 14 any different than what I did with $selected on line 13?

LB1234

ASKER

Thanks Gents!

Radek Baranowski

here you are making actual initialization by assignment:
$selected = ($selected_car == $car_choice) ? "selected" : "";

and here, you try to assign (initialize) $options value of uninitialized variable $options:
$options .= "<option $selected % {$car_choice}>{$car_choice}</option>";

is it clear enough ?

Ray Paseur

PHP only has two string operators.
http://php.net/manual/en/language.operators.string.php

See also:
http://php.net/manual/en/language.operators.assignment.php