5.2 Identifying Elements of an Array


You can access specific values from an array using the array variable's name, followed by the element's key (sometimes called the index) within square brackets:

$age['Fred'] $shows[2]

The key can be either a string or an integer. String values that are equivalent to integer numbers (without leading zeros) are treated as integers. Thus, $array[3] and $array['3'] reference the same element, but $array['03'] references a different element. Negative numbers are valid keys, and they don't specify positions from the end of the array as they do in Perl.

You don't have to quote single-word strings. For instance, $age['Fred'] is the same as $age[Fred]. However, it's considered good PHP style to always use quotes, because quoteless keys are indistinguishable from constants. When you use a constant as an unquoted index, PHP uses the value of the constant as the index:

define('index',5); echo $array[index];               // retrieves $array[5], not $array['index'];

You must use quotes if you're using interpolation to build the array index:

$age["Clone$number"]

However, don't quote the key if you're interpolating an array lookup:

// these are wrong print "Hello, $person['name']"; print "Hello, $person["name"]"; // this is right print "Hello, $person[name]";


Programming PHP
Programming PHP
ISBN: 1565926102
EAN: 2147483647
Year: 2007
Pages: 168

Similar book on Amazon

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net