tableau PHP évitent Undefined offset

Question

Salut je tableau comme ce

$subject_names[7]="English"; 
$subject_names[11]="Software Engeneering"; 

//Student can choose multiple subjects and each subject have int_mark and ext_mark 

$results['Matt'][7]['int_mark'] =15; 
$results['Matt'][7]['ext_mark'] =55; 

$results['Josh'][7]['int_mark'] =12; 
$results['Josh'][7]['ext_mark'] =45; 
$results['Josh'][11]['int_mark'] =14; 
$results['Josh'][11]['ext_mark'] = 52; 

// the array is to maintain crosstab format 

Et pour imprimer ce que je l'ai fait

echo "Student Name\t"; 

foreach($subject_names as $subject_name) 
{ 
    echo "$subject_name\t"; 
} 
echo "<br>"; 

foreach ($results as $student_name => $subjects) 
{ 
    echo "$student_name\t"; 

    foreach($subject_names as $subject_id => $sub_name){ 

     foreach ($subjects[$subject_id] as $mark){ 
      echo "$mark\t"; 
     } 

    } 
    echo "<br>"; 

} 

Comme étudiant "Matt" n'a pas a id_sujet 11 Il me donne un avis erreur

Notice: Undefined offset: 11

Comment puis-je ignorer et l'impression N/A si l'étudiant pas ce sujet

Merci pour toute votre aide et suggestions

Answer 1

Vous pouvez utiliser isset() avec count(): -

if(isset($subjects[$subject_id]) && count($subjects[$subject_id])>0){ 
    foreach ($subjects[$subject_id] as $mark){ 
     echo "$mark\t"; 
    } 
} 

Vous pouvez utiliser !empty() avec count() vérifier aussi: -

if(!empty($subjects[$subject_id]) && count($subjects[$subject_id])>0){ 
    foreach ($subjects[$subject_id] as $mark){ 
     echo "$mark\t"; 
    } 
}