PHP 如何删除空变量的空行或向其添加退格键回显 html 文本输出 - PHP How to delete an empty line of null variable or add backspace to it echo html text output

PHP How to delete an empty line of null variable or add backspace to it echo html text output

如何删除空变量的空行？

例如

$line1 = "Hello All";
$line2 = "Hello You";
$line3 = "Hello Me";
$line2 = null;
Now when i echo 
echo "$line1<br>$line2<br>$line3";
it show empty line in the middle when i set variable to null value, 
So how i can delete this line ? 
i mean i don't want to show empty line. if variable value goes to null
Can i have to make $line2 = null; and then $line2 = something like backspace ?

如何删除空变量的空行？

您的帮助将不胜感激！

注意：我不想在最后一个回显html行中进行编辑，因此您必须在echo之前执行任何操作。我的意思是将$line的值设置为退格或任何其他解决方案。

我无权编辑最后一个回声线，所以在回声语句之前做任何事情。

 echo "$line1<br>$line2<br>$line3";  <== i don't have permission 
 to change a single letter in this line 
 So please make solution before echo line

这个怎么样：

$line1 = "Hello All";
$line2 = "Hello You";
$line3 = "Hello Me";
$line2 = null;
if(!$line2) {
    $line1 .= '<del style="display:none">';
    $line3 = '</del><br>' . $line3;
}
echo "$line1<br>$line2<br>$line3";

您可以做的是检查变量是否为空。

if (!is_null($line1)) {
    echo $line1 . '<br>';
}
//repeat

还是这样做？

$line1 = "Hello All";
$line2 = "Hello You";
$line3 = "Hello Me";
$line2 = null;

打印时：

$output = "$line1<br>$line2<br>$line3";
echo str_replace('<br><br>' , '<br>' , $output );

$line1 = "Hello All";
$line2 = "Hello You";
$line3 = "Hello Me";
$line2 = null;
$array = array($line1,$line2,$line3);
$array = array_filter($array);
foreach($array as $line){
  echo $line.'<br>';
}