Conditional in a function

If I havent set tag “wi-fi”, there is no sense in printing “wi fi 20 euro/week” through $wi_fi_esc

Where are you retrieving the value of the “wi-fi” tag from? Is it a constant? If it is a constant, then you need to declare it like this: $posttags = ‘wi-fi’;

<?php
/*
Plugin Name: MySite-plugin
Description: Site specific code changes for example.com
*/
/* Start Adding Functions Below this Line */
function wpb_author_info_box( $content ) {
 
global $post;
 
// Detect if it is a single post with a post author
if ( is_single() && isset( $post->post_author ) ) {
 
// Get author's display name
$display_name = get_the_author_meta( 'display_name', $post->post_author );
 
// If display name is not available then use nickname as display name
if ( empty( $display_name ) )
$display_name = get_the_author_meta( 'nickname', $post->post_author );
 
// Get author's biographical information or description
$user_description = get_the_author_meta( 'user_description', $post->post_author );

// Get agency period of rentals
$periodo_affitti = get_the_author_meta( 'periodo_affitti', $post->post_author );

$titolo_affitti = '<h4 class="titolo_affitti">Periodo affitti</h4>';

// Get check-in e check-out
$orari = get_the_author_meta( 'orari', $post->post_author );

$titolo_orari = '<h4 class="titolo_affitti">Ingresso e riconsegna</h4>';



// Get prezzo non include
$tassa_soggiorno = '<div class="tassa_soggiorno">'. get_the_author_meta( 'tassa_soggiorno', $post->post_author ) .'</div>';

$supplemento_animali = '<div class="tassa_soggiorno">'. get_the_author_meta( 'supplemento_animali', $post->post_author ) .'</div>';

$supplemento_culla = '<div class="tassa_soggiorno">'. get_the_author_meta( 'supplemento_culla', $post->post_author ) .'</div>';

$importo_cauzione = '<div class="tassa_soggiorno">'. get_the_author_meta( 'importo_cauzione', $post->post_author ) .'</div>';

$servizio_spiaggia = '<div class="tassa_soggiorno">'. get_the_author_meta( 'servizio_spiaggia', $post->post_author ) .'</div>';

$suppl_soggiorni_brevi = '<div class="tassa_soggiorno">'. get_the_author_meta( 'suppl_soggiorni_brevi', $post->post_author ) .'</div>';

$pulizia_esc = '<div class="tassa_soggiorno">'. get_the_author_meta( 'pulizia_esc', $post->post_author ) .'</div>';

$posttags = 'wi-fi';

$wi_fi_esc = ''; 

if (isset($posttags)) { $wi_fi_esc = '<div class="wi_fi_esc">' . get_the_author_meta('wi_fi_esc', $post->post_author) . '</div>'; } 

$biancheria_esc = '<div class="biancheria_esc">'. get_the_author_meta( 'biancheria_esc', $post->post_author ) .'</div>';

$asciugamani_esc = '<div class="asciugamani_esc">'. get_the_author_meta( 'asciugamani_esc', $post->post_author ) .'</div>';




$titolo_prezzo_non_include = '<h4 class="titolo_affitti">Il prezzo non include:</h4>';

//prezzo include

$locazione = '<div class="tassa_soggiorno">'. get_the_author_meta( 'locazione', $post->post_author ) .'</div>';

$commissione = '<div class="tassa_soggiorno">'. get_the_author_meta( 'commissione', $post->post_author ) .'</div>';

$consumi = '<div class="tassa_soggiorno">'. get_the_author_meta( 'consumi', $post->post_author ) .'</div>';

$pulizia_inc = '<div class="tassa_soggiorno">'. get_the_author_meta( 'pulizia_inc', $post->post_author ) .'</div>';

$biancheria_inc = '<div class="tassa_soggiorno">'. get_the_author_meta( 'biancheria_inc', $post->post_author ) .'</div>';

$ac_inc = '<div class="tassa_soggiorno">'. get_the_author_meta( 'ac_inc', $post->post_author ) .'</div>';


$titolo_prezzo_include = '<h4 class="titolo_affitti">Il prezzo include:</h4>';



// Get saldo
$saldo = '<div class="saldo">'. get_the_author_meta( 'saldo', $post->post_author ) .'</div>';

 
// Get author's website URL
$user_website = get_the_author_meta('url', $post->post_author);
 
// Get link to the author archive page
$user_posts = get_author_posts_url( get_the_author_meta( 'ID' , $post->post_author));
 
if ( ! empty( $display_name ) )
 
$author_details = '<h4 class="author_name">Condizioni di pagamento ID: ' . get_the_ID(). '</h4>';
 
if ( ! empty( $user_description ) )

// Author avatar and bio
 
$author_details .= '<p class="author_details">' . get_avatar( get_the_author_meta('user_email') , 90 ) . nl2br( $user_description ). '</p>';
 
$author_details .= '<p class="author_links"><a href="'. $user_posts .'">View all posts by ' . $display_name . '</a>';  
 
// Check if author has a website in their profile
if ( ! empty( $user_website ) ) {
 
// Display author website link
$author_details .= ' | <a href="' . $user_website .'" target="_blank" rel="nofollow">Website</a></p>';
 
} else {
// if there is no author website then just close the paragraph
$author_details .= '</p>';
}

 
// Pass all this info to post content
$content = $content . $titolo_prezzo_include . $locazione  .  $commissione . $consumi . $pulizia_inc . $biancheria_inc . $ac_inc .  $titolo_prezzo_non_include . $pulizia_esc . $tassa_soggiorno . $supplemento_animali . $supplemento_culla . $importo_cauzione . $servizio_spiaggia . $suppl_soggiorni_brevi . $biancheria_esc . $asciugamani_esc . $wi_fi_esc . $ac_esc .  $saldo . '<footer class="author_bio_section" >'. $author_details . $titolo_affitti . $periodo_affitti . $titolo_orari . $orari .'</footer>';
}
return $content;
}
 
// Add our function to the post content filter
add_action( 'the_content', 'wpb_author_info_box' );
 
// Allow HTML in author bio section
remove_filter('pre_user_description', 'wp_filter_kses');
 
/* Stop Adding Functions Below this Line */
?>

The variable $ac_esc is also not declared. It is used when composing $content, but does not exist beforehand.

Wrong:

$content = $content . $titolo_prezzo_include . $locazione . $commissione . $consumi . $pulizia_inc . $biancheria_inc . $ac_inc . $titolo_prezzo_non_include . $pulizia_esc . $tassa_soggiorno . $supplemento_animali . $supplemento_culla . $importo_cauzione . $servizio_spiaggia . $suppl_soggiorni_brevi . $biancheria_esc . $asciugamani_esc . $wi_fi_esc . $ac_esc . $saldo . '<footer class="author_bio_section" >'. $author_details . $titolo_affitti . $periodo_affitti . $titolo_orari . $orari .'</footer>';

Fixed:

$content = $content . $titolo_prezzo_include . $locazione . $commissione . $consumi . $pulizia_inc . $biancheria_inc . $ac_inc . $titolo_prezzo_non_include . $pulizia_esc . $tassa_soggiorno . $supplemento_animali . $supplemento_culla . $importo_cauzione . $servizio_spiaggia . $suppl_soggiorni_brevi . $biancheria_esc . $asciugamani_esc . $wi_fi_esc . $saldo . '<footer class="author_bio_section" >'. $author_details . $titolo_affitti . $periodo_affitti . $titolo_orari . $orari .'</footer>';

Tip 1: with a programme that supports PHP syntax highlighting, you can see something like this right away. E.g. with PHPStorm.

Tip 2: This is about PHP basics. I would recommend to have a closer look at them: https://www.php.net/manual/en/tutorial.php

The function doesnt break the site, this is a half victory, but it is ineffective.

To tell the truth I wanted to do the contrary, I should use the contrary of “isset”. I meant to do the following: when I dont set a specific tag, the variable value is not printed. Maybe each tag has a meta name that is not the one I write in the tags box?

The opposite of isset is when isset returns false. As a condition, it would look like this:

if( !isset($var) ) {
 /* do something if $var is not set */.
}

See: https://www.php.net/manual/de/function.isset.php

So like this:

$var=$posttags;

$posttags = 'wi-fi';

$wi_fi_esc = '';

if( !isset($var) ) {

 $wi_fi_esc = '<div class="wi_fi_esc">' . get_the_author_meta('wi_fi_esc', $post->post_author) . '</div>'; } 

Sorry, I don’t really see the point in the code right now.

I wrote above what I was trying to do

Maybe this is more clear?

"$posttags = animali permessi";

if (isset($posttags)) { $supplemento_animali = '<div class="supplemento_animali">' . get_the_author_meta('supplemento_animali', $post->post_author) . '</div>'; } 

The purpose is displaying the extra cost for pets only if the tag “animali permessi” (pets allowed) is checked.

Finally I got the solution:

if (has_tag( 'animali permessi', $post ) ) {
    $supplemento_animali = '<div class="suppl_animali">'. get_the_author_meta( 'supplemento_animali', $post->post_author ) .'</div>';
}