Programming PHP

The size of the replacement array doesn’t have to be the same as the number of elements
you delete. The array grows or shrinks as needed:
$new = array('law', 'business', 'IS');
array_splice($subjects, 2, 4, $new);
// $subjects is array('physics', 'chem', 'math', 'law', 'business', 'IS')
To get the effect of inserting new elements into the array, delete zero elements:
$subjects = array('physics', 'chem', 'math');
$new = array('law', 'business');
array_splice($subjects, 2, 0, $new);
// $subjects is array('physics', 'chem', 'law', 'business', 'math')
Although the examples so far have used an indexed array, array_splice( ) also works
on associative arrays:
$capitals = array('USA' => 'Washington',
'Great Britain' => 'London',
'New Zealand' => 'Wellington',
'Australia' => 'Canberra',
'Italy' => 'Rome');
$down_under = array_splice($capitals, 2, 2); // remove New Zealand and Australia
$france = array('France' => 'Paris');
array_splice($capitals, 1, 0, $france); // insert France between USA and G.B.
Converting Between Arrays and Variables
PHP provides two functions, extract( ) and compact( ), that convert between arrays
and variables. The names of the variables correspond to keys in the array, and the
values of the variables become the values in the array. For instance, this array:
$person = array('name' => 'Fred', 'age' => 35, 'wife' => 'Betty');
can be converted to, or built from, these variables:
$name = 'Fred';
$age = 35;
$wife = 'Betty';
Creating Variables from an Array
The extract( ) function automatically creates local variables from an array. The
indexes of the array elements are the variable names:
extract($person); // $name, $age, and $wife are now set
If a variable created by the extraction has the same name as an existing one, the
extracted variable overwrites the existing variable.
You can modify extract( )’s behavior by passing a second argument. Appendix A
describes the possible values for this second argument. The most useful value is
124 | Chapter 5: Arrays
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