PHP字符串不连接

Question

I'm reading a file in PHP line by line by using a custom line delimeter, but i'm having difficulty concatenating the line character back onto the string after.

$newhtml = "";
if ($handle) {
          while (($line = stream_get_line($handle, 4096, "</br>")) !== false) 
          {
            $newhtml = "{$line}{$newhtml}" . "</br>";
          }
          echo $newhtml;
          fclose($handle);

I'd be expecting each line of the file to come out on different lines, but the tag isn't even being shown in the dev console.

Answer 1

Actually with your existing block of code below

while (($line = stream_get_line($handle, 4096, "</br>")) !== false) {
    $newhtml = "{$line}{$newhtml}" . "</br>"; // problem happening here with = 
}

You're overwriting the $newhtml value with every while loop iteration.So, you'll get only the last value after the iteration ends. As I understand your requirement, you want to concatenate every line to the $newhtml variable. To do so just modify this like

$newhtml = "{$line}{$newhtml}" . "</br>";

to

$newhtml.= $line."</br>"; // with dot before = 

Look an extra dot( . ) before the equal sign and remove the unnecessary usage of {$newhtml} variable again

Answer 2

From the code you given I can guess that you want to put last line as first, you can use array for this:

<?php
if ($handle) {
    $lines = [];
    while (($line = stream_get_line($handle, 4096, "</br>")) !== false) 
    {
        $lines[] = $line;
    }
    $reversed = array_reverse($lines);
    echo join('<br>' $reversed);
    fclose($handle);
}

But if you just want to display lines as they are in the files, just simplify the code:

<?php
if ($handle) {
    $lines = [];
    while (($line = stream_get_line($handle, 4096, "</br>")) !== false) 
    {
        echo $line . '<br>';
    }
    fclose($handle);
}