如果API值为空，则显示默认值

Question

如果0为空，我想要显示nb_impressions

foreach ($content as $row) {
   $impressions = $row['nb_impressions'];
   print("<td'>$impressions</td>");
}

该值来自HTTP API但是，如果该值为空它显示为空，我怎么能给这些空值0

Answer 1

使用三元运算符检查为

(isset($row['nb_impressions']) && $row['nb_impressions'])并设置默认0

foreach ($content as $row) {
    $impressions = (isset($row['nb_impressions']) && $row['nb_impressions']) ? $row['nb_impressions'] : 0;
    print("<td'>$impressions</td>");
}

在您发表评论之后，您可以将其合并到一个功能中进行检查

function isExist($var,$default=''){
    if (isset($var) && $var) {
        return $var;
    }
    return $default;
}

并使用这样的

$impressions = isExist($row['nb_impressions'], 0);
$clicks= isExist($row['nb_clicks'], 0);
$visits = isExist($row['nb_visits'], 0);

Answer 2

你只需添加if声明

foreach ($content as $row) {
   $impressions = $row['nb_impressions'];
   if(isset($impressions)){
       print("<td'>$impressions</td>");
   }else{
       print("<td>0</td>");
   }
}

Answer 3

使用php empty（）函数进行检查

foreach ($content as $row) {
   if(!empty($row['nb_impressions'])){
       $impressions = $row['nb_impressions'];
   }
   else{
       $impressions = 0;
   }
   print("<td'>$impressions</td>");
}

简直直截了当。