I am studying PHP and i am trying to understand about callback functions, I really looked around at the manual, At stackoverflow and more websites, And i really dont understand what is PHP CallBack Function , If can some one can please help me understand about this functions, I am looking for simple explanation/guide thank you all and have a nice day.
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Do you have read this page? php.net/manual/en/language.types.callable.phpFederkun– Federkun2012-07-21 09:01:03 +00:00Commented Jul 21, 2012 at 9:01
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What is it exactly that you don't understand? What part is unclear?JJJ– JJJ2012-07-21 09:04:53 +00:00Commented Jul 21, 2012 at 9:04
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1 Answer
Take a look at Wikipedia - Callback
In computer programming, a callback is a reference to a piece of executable code that is passed as an argument to other code. This allows a lower-level software layer to call a subroutine (or function) defined in a higher-level layer.
It's a function what you pass to your method or some other function, so it can be called later during that method - function execution.
For example you have callback beforeSave and you want do some logic before saving data to database file etc.. (in one place - DRY). You add logic into beforeSave callback and this callback being called before data saved.
Same is with function on manual for example array_filter($input, callback) it requires that you pass some function to be executed with $input data.
For ex. pass anonymous function:
array_filter($input, function($var) {
// returns whether the input integer is odd
return($var & 1)
});
Will return to you all odd array values, you can change logic in anonymous function to what you want, but array_filter internal mechanic will be always the same (iterator algo)
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Aviel Fedida
Thank you for you answer Aurimas Ličkus, have a nice day.