Some theory

As you know there are two types of methods in PHP classes: static and non-static. To be called a non-static method needs an instance of its class, and static method can be called without instantiating of the class. 

In the meantime there are two very common questions:

• When to use non-static methods and when to use static methods?
• Is there any performance difference between static and non-static methods?

These are very common dilemmas among PHP developers. Most of developers guess that static methods must work faster because there is no object instance with all its properties involved to the call. Sounds logical. Is that actually true?

As I already mentioned above, and as you already know, the main difference between static and non-static metods is that static methods do not need an instance of the class to be called in the code. It means that for static methods there is no need to create object and keep in the memory. So, at least we can save some memory which can also affect the performance? Hmmm... we'll see...

So, it's time to do some very simple experiments for further analysis.

Apparently, the person who wrote this code has never heard about regular expressions. :)

<?php
$find = str_replace(",", "", $find);
$find = str_replace(".", "", $find);
$find = str_replace("/", "", $find);
$find = str_replace(" ", "", $find);
$find = str_replace("-", "", $find);
$find = str_replace("+", "", $find);
$find = str_replace("#", "", $find);
?>

Please, never repeat this! :)

Sometimes you might want to purge a set of similar Redis keys in one shot. So far, standard Redis "DEL" command does not allow to remove keys using patterns. However, there is a trick to do this action. Execute the following command in bash:

redis-cli -h [host] -p [port] KEYS "prefix:*" | xargs redis-cli DEL

Seems clear? Wait a minute! What if you use multiple databases (keyspaces) and need to remove keys from a database different from default (0) one? No problem there! Here is the solution:

If you develop a PHP web application which may be used on a web server with older PHP version, you can run into a situation when some of the PHP functions in your application won't work at all, or won't work as expected.

In fact, you can handle those situations if you want to. However, it can make you application code not as nice as you want and a little heavier.