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for some reasons, our hosting company used PHP 5.2 and doesn't even have mysqli and PDO pre-installed.
I have no choice but to rewrite some part of my code to make it 5.2 compatible.
so, here is my question:
In PHP 5.2 Anonymous function is not supported, so i did the following test to make sure I'm changing the code correctly:
class foo{
public function toString(){
$arr = array("a", "b");
$arr2 = array("c", "d");
print_r(array_map('mapKeyValue', $arr, $arr2));
}
private function mapKeyValue($v, $k){
return $k."='".$v."'";
}
}
$foo = new foo();
echo $foo->toString();
but the above would give me :
Warning: array_map() expects parameter 1 to be a valid callback, function 'mapKeyValue' not found or invalid function name in ....
PHP Warning: array_map() expects parameter 1 to be a valid callback, function 'mapKeyValue' not found or invalid function name in ....
what is the correct way to do :
array_map('mapKeyValue', $arr, $arr2);
within a class?
PS: Is it a good enough reason to change hosting company because they use PHP 5.2?(i got a contract with about 7 month left)
524
A callback function (often referred to as just "callback") is a function which is passed as an argument into another function.
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.
A callback function is a function that occurs after some event has occurred. The reference in memory to the callback function is usually passed to another function. This allows the other function to execute the callback when it has completed its duties by using the language-specific syntax for executing a function.
A callback function is a function that is passed as an argument to another function, to be “called back” at a later time. A function that accepts other functions as arguments is called a higher-order function, which contains the logic for when the callback function gets executed.
Use $this and an array as the callback:
array_map( array( $this, 'mapKeyValue'), $arr, $arr2);
And, just to be sure, this is tested with PHP 5.2.17 and is confirmed working.
84
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