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I was pretty excited to read about anonymous functions in php, which let you declare a variable that is function easier than you could do with create_function. Now I am wondering if I have a function that is passed a variable, how can I check it to determine if it is a function? There is no is_function() function yet, and when I do a var_dump of a variable that is a function::
$func = function(){ echo 'asdf'; }; var_dump($func); I get this:
object(Closure)#8 (0) { } Any thoughts on how to check if this is a function?
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If name of a variable has parentheses (with or without parameters in it) in front of it, PHP parser tries to find a function whose name corresponds to value of the variable and executes it. Such a function is called variable function. This feature is useful in implementing callbacks, function tables etc.
The is_bool() function checks whether a variable is a boolean or not. This function returns true (1) if the variable is a boolean, otherwise it returns false/nothing.
The is_numeric() function checks whether a variable is a number or a numeric string. This function returns true (1) if the variable is a number or a numeric string, otherwise it returns false/nothing.
Definition and Usage. The is_callable() function checks whether the contents of a variable can be called as a function or not. This function returns true (1) if the variable is callable, otherwise it returns false/nothing.
Use is_callable to determine whether a given variable is a function. For example:
$func = function() { echo 'asdf'; }; if( is_callable( $func ) ) { // Will be true. } If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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