Programming PHP

That’s an indexed array, with integer indexes beginning at 0. Here’s an associative
array:
$price['Gasket'] = 15.29;
$price['Wheel'] = 75.25;
$price['Tire'] = 50.00;
// ...
An easier way to initialize an array is to use the array( ) construct, which builds an
array from its arguments:
$addresses = array('spam@cyberpromo.net', 'abuse@example.com',
'root@example.com');
To create an associative array with array( ), use the => symbol to separate indexes
from values:
$price = array('Gasket' => 15.29,
'Wheel' => 75.25,
'Tire' => 50.00);
Notice the use of whitespace and alignment. We could have bunched up the code,
but it wouldn’t have been as easy to read:
$price = array('Gasket'=>15.29,'Wheel'=>75.25,'Tire'=>50.00);
To construct an empty array, pass no arguments to array( ):
$addresses = array( );
You can specify an initial key with => and then a list of values. The values are
inserted into the array starting with that key, with subsequent values having sequential
keys:
$days = array(1 => 'Monday', 'Tuesday', 'Wednesday',
'Thursday', 'Friday', 'Saturday', 'Sunday');
// 2 is Tuesday, 3 is Wednesday, etc.
If the initial index is a non-numeric string, subsequent indexes are integers beginning
at 0. Thus, the following code is probably a mistake:
$whoops = array('Friday' => 'Black', 'Brown', 'Green');
// same as
$whoops = array('Friday' => 'Black', 0 => 'Brown', 1 => 'Green');
Adding Values to the End of an Array
To insert more values into the end of an existing indexed array, use the [] syntax:
$family = array('Fred', 'Wilma');
$family[] = 'Pebbles'; // $family[2] is 'Pebbles'
This construct assumes the array’s indexes are numbers and assigns elements into the
next available numeric index, starting from 0. Attempting to append to an associative
118 | Chapter 5: Arrays
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