Category Archives: micro tutorial

Object Cloning and Passing by Reference in PHP

micro tutorial, PHP, , , , , , , , , , , ,

In PHP everything’s a reference! I’ve heard it so many times in my practice. No, these words are too strong! Let’s see some examples.

Passing by reference in PHP can be tricky!
Some developers think that everything's passed by reference in PHP.

Passing Parameters by Reference

Clearly when we pass parameters to a function it’s not by reference. How to check this? Well, like this.

function f($param)
{
	$param++;
}
 
$a = 5;
f($a);
 
echo $a;

Now the value of $a equals 5. If it were passed by reference, it would be 6. With a little change of the code we can get it.

function f(&$param)
{
	$param++;
}
 
$a = 5;
f($a);
 
echo $a;

Now the variable’s value is 6.

So far, so good. Now what about copying objects?
Continue reading Object Cloning and Passing by Reference in PHP →

Thing to Know About PHP Arrays

micro tutorial, PHP, , , , , , , , , , , , , , , , , ,

Consider the following case. We have an array with identical keys.

$arr = array(1 => 10, 1 => 11);

What happens when the interpreter reaches this line of code? This is not a syntax error and it is completely valid. Very similar, but more interesting case is when we have an array of identical keys, where those identical keys are represented once as an integer and then as a string.

Keys in PHP arrays are not type sensitive, so pay attention when using them!
Keys in PHP arrays are not type sensitive, so pay attention when using them!

$arr = array(1 => 10, "1" => 11);

Now several questions arise. First of all, how many elements have this array? Two or one. This can be easily verified by checking what count() will return. Continue reading Thing to Know About PHP Arrays →

Powerful PHP: Less Known String Manipulation

micro tutorial, PHP, , , , , , , ,

Yet another thing that’s great in PHP is the power you have when doing some string manipulation/operation. Here’s something that is really useful, but I think it remains a bit unknown. Let’s imagine you need to take the first (or whatever) character of a string. Most developers go to the obvious:

$str = 'hello world';
echo substr($str, 0, 1); // outputs "h"

But here’s something better and cleaner.

echo $str{0}; // outputs "h"

This code chunk return the first character of $str, but it can be used with the same success for any other character of the string. In my opinion this is more cleaner and its really syntactically self documented.

This approach can be useful when trying to check whether the first symbol for instance is “?” or “/”.

PHP: Fetch $_GET as String with http_build_query()

micro tutorial, PHP, , , , , , , , , , , ,

PHP is really full of functions for everything! Most of the time when you try to do something with strings, there’s a function that can do it better and faster.

The Route from $_GET to String

The global arrays in PHP contain request parameters. Either GET or POST. As you know if the page address is something like:

http://www.example.com/index.php?a=b&key=value

This means that you pass to the index.php file two parameters – “a” and “key” with their values: “b” and “value”. Now in this case you can dump the $_GET global array somewhere in index.php and you’ll receive something like this.

array(
	"a"   => "b",
	"key" => "value",
);

This is however pseudocode, but in fact $_GET will be very similar to this sample array. Continue reading PHP: Fetch $_GET as String with http_build_query() →

PHP Strings: How to Get the Extension of a File

micro tutorial, PHP, , , , , , , , ,

EXE or GIF or DLL or …

Most of the code chunks I’ve seen about getting a file extension from a string are based on some sort of string manipulation.

Get the Filename Extension with PHP
If you want to get the filename extension with PHP is better to use pathinfo() than string manipulations

$filename = '/my/path/image.jpeg';
echo substr($filename, strrpos($filename, '.') + 1);

Howerver there is a more elegant solution.

$filename = '/my/path/image.jpeg';
echo strtolower(pathinfo($filename, PATHINFO_EXTENSION));

Thus you rely on PHP built in functions and it’s harder to overlook the exact string manipulation approach.