Undefined variable Output

Question

I am getting the following error in debug mode from my wordpress theme. Likely a very easy fix but I dont see what to do.

UNDEFINED VARIABLE: OUTPUT .... line 34 ($output variable)

$categories = get_the_category();
if($categories) {
    foreach($categories as $category) {
        $output .= '<a href="'.get_category_link( $category->term_id ).'" class="btn-standard-blog" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '">'.$category->cat_name.'</a>';
    }
}
echo $output;

What would happen if $categories was false?

gen_Eric
– gen_Eric

2013-12-23 15:58:05 +00:00
Commented Dec 23, 2013 at 15:58 — gen_Eric
– gen_Eric, Commented Dec 23, 2013 at 15:58

Funk Forty Niner · Accepted Answer · 2013-12-23 15:57:40Z

4

$output only exists if the the condition of your IF statement is met. Otherwise you are trying to use a variable that is not yet defined. This is especially true in your case as the first iteration of your loop attempts to add a value to a non-existant value as well so this error will always occur in this code.

You can solve this by declaring this variable with no value and then modifying it when appropriate.

<?php 
$output = '';
$categories = get_the_category();
    if($categories) {
        foreach($categories as $category) {
            $output .= '<a href="'.get_category_link( $category->term_id ).'" class="btn-standard-blog" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '">'.$category->cat_name.'</a>';
    }
}
echo $output; ?>

edited Dec 23, 2013 at 15:57

Funk Forty Niner

74.2k14 gold badges71 silver badges146 bronze badges

answered Dec 23, 2013 at 15:54

John Conde

220k100 gold badges464 silver badges504 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

memyselfandmyiphone Over a year ago

so simple, silly mistake...Thank you. I will accept when the time limit is up

Boaz Over a year ago

@AlbaClan In general, it's best to initialize variables before using them. More on this subject in this question.

Collectives™ on Stack Overflow

Undefined variable Output

1 Answer 1

2 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Linked

Related