Question

I am doing this to check and already use the variable of type number in php:

$myvar = $myvar * 1;

with this, I have a number or if $myvar has any other caracter, the result is 0

I wonder if this can somehow trouble me in the future.

for preventing sake, I am using a function that englobes that above code so I can change it if needed. Eg:

$myvar = IntOrZero($myvar);

so my question if this is a goodway to check and use the number variable?

EDIT:
Using a * 1, I am sure that it will return me a variable of type number.
See:

$var = "350";
$num = 120;
// builtin
if (is_numeric($var))
  echo($var - $num);

// multiplying
$var *= 1;
echo($var - $num);

While I am not sure if the builtin method would echo what I want, I am sure that the multiplying will.
I kinda don’t care if the $var is a number or not, I won’t show any message to the user if it is not, I will work with the 0 value if it is not a number. Based on answers, would this be a good way?

function IntOrZero($var){
   return is_numeric($var) ? intval($var) : 0;
}

thanks,
Joe

Answer 1

No, it’s not a good way, and here’s why:

$ php -r 'echo array() * 1;'
Fatal error: Unsupported operand types in Command line code on line 1

To make sure a variable is a number, cast it:

$integer = (int)$integer;
$float = (float)$float;

To check whether it’s a number or not:

is_numeric($var)    // number or string containing any valid numeric expression
ctype_digit($var)   // string containing only digits
is_int($var)        // is of type int
is_float($var)      // is of type float

These are all slightly different, depending on what exactly you want to check for. Refer to the documentation:

http://php.net/is_numeric
http://php.net/manual/en/function.ctype-digit.php
http://php.net/is_int
http://php.net/is_float