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The is_null () function checks whether a variable is NULL or not. This function returns true (1) if the variable is NULL, otherwise it returns false/nothing.
27 sty 2017 · You can use php variable handling function is_null(mixed $var) which returns TRUE if var is null, otherwise FALSE. <?php $foo = NULL; $bar = 'NULL'; var_dump(is_null($foo), is_null($bar)); ?> OUTPUT. bool(true) bool(false)
This MSAccess tutorial explains how to use the Access IsNull function with syntax and examples. The Microsoft Access IsNull function returns TRUE if the expression is a null value. Otherwise, it returns FALSE.
Definition and Usage. The IsNull () function checks whether an expression contains Null (no data). This function returns a Boolean value. TRUE (-1) indicates that the expression is a Null value, and FALSE (0) indicates that the expression is not a Null value. Syntax. IsNull (expression) Parameter Values. Technical Details. More Examples. Example.
9 sty 2024 · In this article, we will explore several ways to check if a variable is NULL in PHP, outlining the steps, code examples, performance considerations, and discussing the pros and cons of each method.
A second look into the PHP specs tells that is_null() checks whether a value is null or not. So, you may pass any VALUE to it, eg. the result of a function. isset() on the other hand is supposed to check for a VARIABLE's existence, which makes it a language construct rather than a function.
The following example uses the is_null () to check if the element with the key link is null or not. It returns true because the element doesn’t exist: <?php $colors = [ 'text' => 'black', 'background' => 'white' ]; var_dump (is_null ($colors['link']));Code language:PHP(php) It also returns a notice:
