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Web Technologies-I

Notes Initializing Numerically Indexed Arrays
To create the array shown, use the following line of PHP code:
$products = array( ‘Tires’, ‘Oil’,

‘Spark Plugs’ );
This will create an array called products containing the three values given—’Tires’, ‘Oil’,
and ’Spark Plugs’. Note that, like echo, array() is actually a language construct rather than
a function.

Depending on the contents you need in your array, you might not need to manually initialize
them as in the preceding example.
If you have the data you need in another array, you can simply copy one array to another using
the = operator.
If you want an ascending sequence of numbers stored in an array, you can use the range()function
to automatically create the array for you. The following line of code will create an array called
numbers with elements ranging from 1 to 10:
$numbers = range(1,10);
If you have the information stored in file on disk, you can load the array contents directly from
the file.
If you have the data for your array stored in a database, you can load the array contents directly
from the database. You can also use various functions to extract part of an array or to reorder
an array.

Accessing Array Contents
To access the contents of a variable, use its name. If the variable is an array, access the contents
using the variable name and a key or index. The key or index indicates which stored values we
access. The index is placed in square brackets after the name.
Type $products[0], $products[1], and $products[2] to use the contents of the products array.

Element zero is the first element in the array. This is the same numbering scheme as used in
C, C++, Java, and a number of other languages, but it might take some getting used to if you
are not familiar with it.
As with other variables, array elements’ contents are changed by using the = operator. The
following line will replace the first element in the array ‘Tires’ with ‘Fuses’.
$products[0] = ‘Fuses’;
The following line could be used to add a new element—’Fuses’, to the end of the array, giving
us a total of four elements:
$products[3] = ‘Fuses’;

To display the contents, we could type:
echo “$products[0] $products[1] $products[2] $products[3]”;

Like other PHP variables, arrays do not need to be initialized or created in advance. They are
automatically created the first time you use them.

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