![]() ![]() The following is an example of how to test if a variable is set, whether or not it is NULL. ![]() On a similar note, if _get always returns but instead issues warnings or notices then those will surface. Testing if ->nosuch->foo exists: (getting nosuch) Property does not exist! Testing if ->nosuch exists: (isset nosuch?) No Uncomment the echos in the methods and you'll see exactly what happened: Testing if ->nosuch->foo exists: Property does not exist! If (isset( $obj -> irrelevant )) echo "Yes" else echo "No" If (isset( $obj -> nosuch -> foo )) echo "Yes" else echo "No" Įcho "\nTesting if ->irrelevant exists: " If (isset( $obj -> nosuch )) echo "Yes" else echo "No" Įcho "\nTesting if ->nosuch->foo exists: " isset($object->nosuch) will behave normally but isset($object->nosuch->foo) will crash. ![]() Imagine you have a class with a normal _isset and a _get that fatals for non-existant properties. Note that isset() is not recursive as of the 5.4.8 I have available here to test with: if you use it on a multidimensional array or an object it will not check isset() on each dimension as it goes. Var_dump ( $def -> ghi -> jkl ) // null / E_NOTICE: Trying to get property of non-object Var_dump ( $def -> ghi ) // null / E_NOTICE: Trying to get property of non-object Var_dump ( $def ) // null / E_NOTICE: Trying to get property of non-object Var_dump ( $abc -> def -> ghi -> jkl ) // null / E_NOTICE: Trying to get property of non-object Var_dump ( $abc -> def -> ghi ) // null / E_NOTICE: Trying to get property of non-object Var_dump ( $abc ) // object(stdClass)#1 (1) Var_dump (isset( $def -> ghi -> jkl )) // bool(false) Var_dump (isset( $def -> ghi )) // bool(false) Var_dump (isset( $abc -> def -> ghi -> jkl )) // bool(false) Var_dump (isset( $abc -> def -> ghi )) // bool(false) Var_dump (isset( $abc -> def )) // bool(true) Without raising any errors, warnings or notices. Isset($abc) & isset($abc->def) & isset($abc->def->ghi) You can safely use isset to check properties and subproperties of objects directly. Getting Started Introduction A simple tutorial Language Reference Basic syntax Types Variables Constants Expressions Operators Control Structures Functions Classes and Objects Namespaces Enumerations Errors Exceptions Fibers Generators Attributes References Explained Predefined Variables Predefined Exceptions Predefined Interfaces and Classes Context options and parameters Supported Protocols and Wrappers Security Introduction General considerations Installed as CGI binary Installed as an Apache module Session Security Filesystem Security Database Security Error Reporting User Submitted Data Hiding PHP Keeping Current Features HTTP authentication with PHP Cookies Sessions Dealing with XForms Handling file uploads Using remote files Connection handling Persistent Database Connections Command line usage Garbage Collection DTrace Dynamic Tracing Function Reference Affecting PHP's Behaviour Audio Formats Manipulation Authentication Services Command Line Specific Extensions Compression and Archive Extensions Cryptography Extensions Database Extensions Date and Time Related Extensions File System Related Extensions Human Language and Character Encoding Support Image Processing and Generation Mail Related Extensions Mathematical Extensions Non-Text MIME Output Process Control Extensions Other Basic Extensions Other Services Search Engine Extensions Server Specific Extensions Session Extensions Text Processing Variable and Type Related Extensions Web Services Windows Only Extensions XML Manipulation GUI Extensions Keyboard Shortcuts ? This help j Next menu item k Previous menu item g p Previous man page g n Next man page G Scroll to bottom g g Scroll to top g h Goto homepage g s Goto search
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