Editing PHP (section)

=== Data types ===
PHP is [[strong and weak typing|loosely typed]]. It stores integers in a platform-dependent range, either as a 32, 64 or 128-bit [[signed number representations|signed]] [[integer (computer science)|integer]] equivalent to the [[C variable types and declarations|C-language long type]]. Unsigned integers are converted to signed values in certain situations, which is different behaviour to many other programming languages.<ref>{{cite web | url = http://www.mysqlperformanceblog.com/2007/03/27/integers-in-php-running-with-scissors-and-portability/ | title = Integers in PHP, running with scissors, and portability | date = March 27, 2007 | publisher = MySQL Performance Blog | access-date = 2007-03-28}}</ref> Integer variables can be assigned using decimal (positive and negative), [[octal]], [[hexadecimal]], and [[binary number|binary]] notations.<ref>{{cite web|access-date=2025-05-26|url=https://www.php.net/manual/en/language.types.integer.php|title=Integers|website=PHP Manual |publisher=The PHP Group}}</ref>

[[Floating-point number]]s are also stored in a platform-specific range. They can be specified using floating-point notation, or two forms of [[scientific notation]].<ref name="The PHP Group-2">{{cite web|access-date=2008-03-16|url=https://www.php.net/manual/en/language.types.php|title=Types |publisher=The PHP Group}}</ref> PHP has a native [[Boolean data type|Boolean]] type that is similar to the native Boolean types in [[Java (programming language)|Java]] and [[C++]]. Using the Boolean type conversion rules, non-zero values are interpreted as true and zero as false, as in [[Perl]] and C++.<ref name="The PHP Group-2" />

The null data type represents a variable that has no value; <code>NULL</code> is the only allowed value for this data type.<ref name="The PHP Group-2" />

Variables of the "resource" type represent references to resources from external sources. These are typically created by functions from a particular extension, and can only be processed by functions from the same extension; examples include file, image, and database resources.<ref name="The PHP Group-2" />

Arrays can contain elements of any type that PHP can handle, including resources, objects, and even other arrays. Order is preserved in lists of values and in [[hash table|hashes]] with both keys and values, and the two can be intermingled.<ref name="The PHP Group-2" /> PHP also supports [[string (computing)|strings]], which can be used with single quotes, double quotes, nowdoc or [[heredoc]] syntax.<ref>{{cite web|access-date=2008-03-21|url=https://www.php.net/manual/en/language.types.string.php|title=Strings |publisher=The PHP Group}}</ref>

The '''Standard PHP Library''' (SPL) attempts to solve standard problems and implements efficient data access interfaces and classes.<ref>{{cite web | url = https://www.php.net/spl | title = SPL&nbsp;– StandardPHPLibrary | date = March 16, 2009 | website = PHP.net | access-date = 2009-03-16}}</ref>