What is an Array?
An array
is a special variable, which can hold more than one value at a time.
An array
is a data structure that stores one or more values in a single value. For
experienced programmers it is important to note that PHP's arrays are actually
maps (each key is mapped to a value).
In
PHP, there are three types of arrays:
- Indexed arrays - Arrays with
numeric index
- Associative
arrays
- Arrays with named keys
- Multidimensional
arrays
- Arrays containing one or more arrays
If
you have a list of items (a list of car names, for example), storing the cars
in single variables could look like this:
$cars1="Volvo";
$cars2="BMW";
$cars3="Toyota";
However,
what if you want to loop through the cars and find a specific one? And what if
you had not 3 cars, but 300?
The
solution is to create an array!
1)A Numerically Indexed Array
·
If
this is your first time seeing an array, then you may not quite understand the
concept of an array. Imagine that you own a business and you want to store the
names of all your employees in a PHP variable. How would you go about this?
·
It
wouldn't make much sense to have to store each name in its own variable.
Instead, it would be nice to store all the employee names inside of a single
variable.
Example:
<!DOCTYPE
html>
<html>
<body>
<?php
$cars=array("Volvo","BMW","Toyota");
echo "I like " . $cars[0] . ", " . $cars[1] . " and
" . $cars[2] . ".";
?>
</body>
</html>
Output:
I like
Volvo, BMW and Toyota.
2) PHP Associative Arrays:
In an associative array a key is associated with a
value. If you wanted to store the salaries of your employees in an array, a
numerically indexed array would not be the best choice. Instead, we could use
the employees names as the keys in our associative array, and the value
would be their respective salary.
Example:
$salaries["Bob"]
= 2000;
$salaries["Sally"]
= 4000;
$salaries["Charlie"]
= 600;
$salaries["Clare"]
= 0;
echo "Bob is being
paid - $" . $salaries["Bob"] . "<br />";
echo "Sally is being
paid - $" . $salaries["Sally"] . "<br />";
echo "Charlie is
being paid - $" . $salaries["Charlie"] . "<br
/>";
echo "Clare is being
paid - $" . $salaries["Clare"];
Output:
Bob is being paid - $2000
Sally is being paid - $4000
Charlie is being paid - $600
Clare is being paid - $0
3) PHP Multidimensional
Arrays:
An array can also contain another
array as a value, which in turn can hold other arrays as well. In such a way we
can create two- or three-dimensional arrays:
Example:
<!DOCTYPE html>
<html>
<body>
<?php
// A two-dimensional array
$cars = array
(
array("Volvo",100,96),
array("BMW",60,59),
array("Toyota",110,100)
);
echo $cars[0][0].": Ordered: ".$cars[0][1].". Sold:
".$cars[0][2]."<br>";
echo $cars[1][0].": Ordered: ".$cars[1][1].". Sold:
".$cars[1][2]."<br>";
echo $cars[2][0].": Ordered: ".$cars[2][1].". Sold:
".$cars[2][2]."<br>";
?>
</body>
</html>
Output:
Volvo: Ordered: 100. Sold: 96
BMW: Ordered: 60. Sold: 59
Toyota: Ordered: 110. Sold: 100
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