https://stackoverflow.com › questions › 418066

PHP shows that $a['b'] exists, and has a NULL value. If you add: var_dump(isset($a['b'])); var_dump(isset($a['c'])); you can see the ambiguity I'm talking about with the isset() function. Here's the output of all three of these var_dump()s: array(1) { ["b"]=> NULL } bool(false) bool(false)

https://www.w3schools.com › php › func_var_isset.asp

The isset() function checks whether a variable is set, which means that it has to be declared and is not NULL. This function returns true if the variable exists and is not NULL, otherwise it returns false. Note: If multiple variables are supplied, then this function will return true only if all of the variables are set.

https://stackoverflow.com › questions › 14414379

If you need to check if a property exists in a class, then you can use the build in function property_exists() Example: if (property_exists('class', $property)) { //do something }

https://www.php.net › manual › en › function.property-exists

This function checks if the given property exists in the specified class. Note: As opposed with isset(), property_exists() returns true even if the property has the value null.

https://www.php.net › manual › fr › function.method-exists

The function does not care about class existance, so you can use it to check an existance of a method even when class was not declared e.g. <?php if( method_exists ( 'THIS_WAS_NOT_DECLARED' , 'some_method' ) )

https://www.phptutorial.net › php-tutorial › php-in_array

In this tutorial, you will learn how to use the PHP in_array() function to check if a value exists in an array.

https://www.phptutorial.net › php-oop › php-property_exists

PHP property_exists function examples. The following example uses the property_exists() function to check if the FileReader class has a specific property: <?php class FileReader { private $filename; public $done; protected $filesize; public static $mimeTypes; } var_dump(property_exists(FileReader::class, 'filename')); // true .

https://www.php.net › manual › en › function.function-exists

method_exists() - Checks if the class method exists; is_callable() - Verify that a value can be called as a function from the current scope. get_defined_functions() - Returns an array of all defined functions; class_exists() - Checks if the class has been defined; extension_loaded() - Find out whether an extension is loaded

https://www.delftstack.com › howto › php › check-if-property-exists-in-php

PHP gives us two straightforward solutions that we can use to check if a specific property exists in an object and then execute a particular piece of code. This article will introduce these two ways to check if a property exists in an object or class in PHP. Use property_exists() to Check if a Property Exists in PHP. The property ...

https://www.phptutorial.net › php-tutorial › php-file-exists

Use the file_exists() function to check if a file exists. Use the is_file() function to check if a path is a regular file, not a directory, and that file exists. Use the is_readable() function to check if a file exists and readable.