How to understand isset in codeigniter(php)?

Question

Hey I'm new to php and codeigniter. I know codeigniter has an isset function. what does the following code mean? Can someone please help

<?php echo isset($error) ? $error : ''; ?>

Yes, you can echo variable like that. So what is your question? — ArtOsi, May 18 '18 at 06:50
To me that just says "If $error is set, echo it, if not, echo nothing". I'm confused as to what information you are looking for. — Stephen, May 18 '18 at 06:52
in controller class i write $data['error'] = 'your input is invalid'; — Farhan Kazmi, May 18 '18 at 06:53
You need to give a more detailed example of your code and what you're trying to achieve. Followed by the specific error when you do. The first example you gave is just a perfectly well-formed ternary operator that should do exactly what it says on the tin. — Stephen, May 18 '18 at 06:55

score 2 · Answer 1 · answered May 18 '18 at 08:07

isset is a php function, you can use it without CodeIgnitor, but it basically checks to see if the variable has been set yet.

$someVariable = 'This variable has been set';

var_dump(isset($someVariable)); // True
var_dump(isset($anotherVariable)); // False

the ? and : parts tell PHP what to do. It's called a ternary operator, and can be thought as as a short if statement:

echo isset($someVariable) ? 'set' : 'not set';

is the same as:

if (isset($someVariable)) {
    echo 'set';
} else {
    echo 'not set';
}

1 Answers1