[RESOLVED] 0 Not Numeric?

[jameseymour]

I am validating a users input to make sure it is numeric. So I used the function:

function check_absorbance($absorbance)
{
  if(is_numeric($absorbance)==TRUE)
      return TRUE;
  else
    return FALSE;
}

For some reason the number 0 is not validating. So I changed my function to:

function check_absorbance($absorbance)
{
  if(is_numeric($absorbance)==TRUE)
  {
    if($absorbance=="0")
      return FALSE;
    else
      return TRUE;
  }
  else
    return FALSE;
}

Yet 0 still does not validate. The user inputs the data in a text box. I trim the variable of all other characters so it is just the 0 there. Anyone see what I am doing wrong here?

[bogu]

This "0" is a string, but this 0 si integer ...

[jameseymour]

Ah, should have noticed that, thanks.

[bogu]

U can mark this thread as RESOLVED ...

[jameseymour]

Done

[Installer]

Whether the data is a string ("0") or integer (0), is_numeric() will return true. (And for that matter the data will always be string if it's user input. And integer data will be cast to string within the function.) Your first function should work, and in fact does. Your second function "works", too, in that it returns false from the first return statement as it should, with both "0" and 0 passed to it.

From the manual:

is_numeric -- Finds whether a variable is a number or a numeric string

An integer is treated the same way because of automatic casting.

$x = 0;

if ($x == '0') {
    echo 'string';  // echoed
} else {
    echo 'integer';
}

if ($x === '0') {
    echo 'string';
} else {
    echo 'integer';  // echoed
}