Page 123 - Open Soource Technologies 304.indd

Open Source Technologies

Notes The output of this example is
#0 = Peter

#1 = Barbara

#2 = Bill
#3 = Nancy

7.8.8 Reset( )

Iteration in PHP is done by using an internal array pointer that keeps record of the current
position of the traversal. Unlike with foreach(), when you want to use each() to iterate over an
array, you must reset() the array before you start to iterate over it. In general, it is best for you
to always use foreach() and not deal with this subtle nuisance of each() traversal.
7.8.9 Each( )

The each( ) function returns the current key/value pair and advances the internal pointer to the
next element. When it reaches the end of of the array, it returns a booloean value of false. The
key/value pair is returned as an array with four elements: the elements 0 and “key”, which
have the value of the key, and elements 1 and “value”, which have the value of the value. The
reason for duplication is that, if you’re accessing these elements individually, you’ll probably
want to use the names such as
$elem[“key”] and $elem[“value”]:

$ages = array(“Peter” => 28, “Barbara” => 67);
reset($ages);

$person = each($ages);
print $person[“key”];

print “ is of age “;
print $person[“value”];

This prints
Peter is of age 28

When we explain how the list() construct works, you will understand why offsets 0 and 1 also
exist.
7.8.10 List( )
The list( ) construct is a way of assigning multiple array offsets to multiple variables in one
statement:
list($var1, $var2, ...) = $array;
The first variable in the list is assigned the array value at offset 0, the second is assigned offset 1,
and so on. Therefore, the list() construct translates into the following series of PHP statements:
$var1 = $array[0];

118 LOVELY PROFESSIONAL UNIVERSITY