Memory management

Quite often, PHP developers need to deal with a large amount of data. While large is a relative term, memory is not. Certain combinations of functions and language constructs, when used irresponsibly, can clog our server memory in a matter of seconds. 

Probably the most notorious function is file_get_contents(). This easy-to-use function literally grabs the content of an entire file and puts it into memory. To better understand the issue, let's take a look at the following example:

<?php

$content = file_get_contents('users.csv');
$lines = explode("\r\n", $content);

foreach ($lines as $line) {
  $user = str_getcsv($line);
  // Do something with data from $user...
}

While this code is perfectly valid and working, it is a potential performance bottleneck. The $content variable will pull the content of the entire users.csv file into memory. While this could work for a small file size, of let's say a couple of megabytes, the code is not performance optimized. The moment users...