Keep certain number of lines - php

Question

I want to keep just an exact number of line from this, it takes a file reverse it and echo it, but the file might get to long and want to limit it to a number of lines.
$file = file("update.log");
$file = array_reverse($file);
foreach($file as $f){
if (stripos($f, "Sale") !== false) {
$class = "sales";
} else{
$class = "row";
}
echo "<div class='".$class." scale'>".$f."</div>";
}

Answer 1

Use a counter and when it hits the max_lines number break out of the foreach loop.
$file = file("update.log");
$file = array_reverse($file);
$count = 0;
$max_lines = 100;
foreach($file as $f){
if ($count >= $max_lines){
break;
}
if (stripos($f, "Sale") !== false) {
$class = "sales";
} else{
$class = "row";
}
$count++;
echo "<div class='".$class." scale'>".$f."</div>";
}

Answer 2

$file = file("update.log");
$file = array_reverse($file);
$lineLimit = 25;
$lineCounter = 0;
foreach($file as $f){
if (stripos($f, "Sale") !== false) {
$class = "sales";
} else{
$class = "row";
}
echo "<div class='".$class." scale'>".$f."</div>";
$lineCounter++;
if($lineCounter > $lineLimit)
break; //Will exit the loop
}

Answer 3

I think this is faster and more flexible in avoiding memory problems. You don't have to read every line of the file so you could use something like this:
function viewLastLines($logfile,$maxlines=25) {
$handle = fopen($logfile, "r");
fseek($handle, -($maxlines),SEEK_END);
while (($line = fgets($handle)) !== false)
$outputlines[]=$line;
fclose($handle);
return $outputlines;
}
Use it like this in your case:
$file = array_reverse(viewLastLines("update.log",100));
foreach($file as $f){
if (stripos($f, "Sale") !== false) $class = "sales";
else $class = "row";
echo "<div class='".$class." scale'>".$f."</div>";
}