How do you change a text variable to an int in PHP?

I have a variable that is definited by a POST call from a form where it is inputed into a text field. Is there any way to convert this variable to an interger?

From the form:

Lenght: <input name="length" value="10" type="text" id="lenght" size="2" />

From the php code:

$length = $_POST['lenght'];
$url = substr($url, 0, $length);

This doesn't seem to work and the only reason why I think it isn't working is because $lenght is defined as text and not an interger.

From stackoverflow

• Seems to be a spelling error in your code: length vs. lenght - that could be your problem right there.

  To do an explicit conversion, use the intval() function

  $length = intval($_POST['length']);
  

• It likely doesn't work because you misspelled length twice, instead of zero or three times.

  Eric Petroelje : I laughed - seen plenty of code like that though. As long as you spell it wrong every time there's no problem right?

  Michael Myers : Actually, I count three of each spelling, not counting the text of the question.

  Ilya Birman : Cool explanation :-)

• Two things:

  1. It doesn't work because you misspelled length <-> lenght

  2. The correct way to convert a string to an integer is using the function intval.

  ---

  $length = intval($_POST['length']);
  $url = substr($url, 0, $length);
  

• If you are sure that the value you are looking at has a correct representation for the type you want to convert to, you can also use a vanilla type cast operation:

  $int = (int) "1"; // var_dump($int) => int(1)
  $float = (float) "1.2345"; // var_dump($float) => float(1.2345)
  

  Beware of incorrect representations of the variable that you are converting though, i.e casting "a random string" to a number might not yield the results you expect. If you are handling user input, you're better of using the above suggested solutions with function calls such as intval and floatval

• Ignoring the misspellings of 'length' above, there are a few ways to explicitly convert a string into an integer in PHP. Usually this conversion will happen automatically. Take the following code:

  $numeric_string = '42';
  echo ($numeric_string * 2);
  

  This will print out "84", as expected. See the reference on Type-Juggling.

  If you KNOW that the string you have is a number (perhaps by checking is_numeric()) then you can either cast the variable to an Integer

  $numeric_string = '42';
  $converted_integer = (int) $numeric_string;
  // or
  $converted_integer = (integer) $numeric_string;
  

  or use intval()

  $numeric_string = '42';
  $converted_integer = intval($numeric_string);
  

  An important point to remember about intval() is that it will return a 0 if it can't resolve the string into an Integer. This could (potentially) give you a second way to check for errors (after is_numeric()), or it could cause unexpected results if you aren't properly insuring that the variable is numeric to begin with.