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Unit 7: Functions

$var2 = $array[1]; Notes
...

As previously mentioned, the indexes 0 and 1 returned by each() are used by the list() construct.
You can probably already guess how the combination of list() and each() work. Consider the
highlighted line from the previous $players traversal example:

$players = array(“Peter”, “Barbara”, “Bill”, “Nancy”);

reset($players);
while (list($key, $val) = each($players)) {

print “#$key = $val\n”;

}
What happens in the boldfaced line is that during every loop iteration, each() returns the current
position’s key/value pair array, which, when examined with print_r(), is the following array:

Array
(

[1] => Peter
[value] => Peter

[0] => 0

[key] => 0
)

Then, the list() construct assigns the array’s offset 0 to $key and offset 1

to $val.
7.8.11 Additional Methods for Traversing Arrays

You can use other functions to iterate over arrays including current() and next(). You shouldn’t
use them because they are confusing and are legacy functions. In addition, some standard
functions allow all sorts of elegant ways of dealing with arrays such as array_walk(), which is
covered in a later unit.

7.9 Objects

The main difference in OOP as opposed to functional programming is that the data and code are
bundled together into one entity, which is known as an object. Object-oriented applications are
usually split up into a number of objects that interact with each other. Each object is usually an
entity of the problem, which is self-contained and has a bunch of properties and methods. The
properties are the object’s data which basically means the variables that belong to the object.
The methods if you are coming from a functional background are basically the functions that
the object supports. Going one step further, the functionality that is intended for other objects
to be accessed and used during interaction is called an object’ sinter face.

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