I want my form input as an integer... but only if it was submitted as such

Question

Since it appears intval only returns 0 if it's not an integer (and I want 0 sometimes in the input), and also since is_int doesn't evaluate string input to tell me if it's an integer (and I'm simply not familiar with what casting a variable as (int) does if it's not an integer).

What's the correct way to go about this?

possible duplicate of [Checking if a string holds an integer](http://stackoverflow.com/questions/3377537/checking-if-a-string-holds-an-integer) — outis, Mar 11 '11 at 20:25
I suppose it is. I'll just use `if((string)(int)$var == $var)` then. Thanks! — Hamster, Mar 11 '11 at 20:41

score 1 · Accepted Answer · answered Mar 11 '11 at 20:23

1

You might want to take a look at the ctype_digit() function (quoting) :

bool ctype_digit ( string $text )
Returns TRUE if every character in the string $text is a decimal digit, FALSE otherwise.

Using this to test what the input is made of, you should then be able to decide what to do with it, depending on the fact it contains an integer or not.

I suppose something like this should do the trick :

if (ctype_digit($_POST['your_field'])) {
    // it's an integer => use it
} else {
    // Not an integer
}

answered Mar 11 '11 at 20:23

Pascal MARTIN

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I'm out of votes, so have a textual +1. Everyone always forgets about poor old ctype. – Charles Mar 11 '11 at 20:25
Yeah, it's not quite well-known, it seems : I've had this same questions a few days ago from a colleague, at work ^^ – Pascal MARTIN Mar 11 '11 at 20:32
Guess this could work, but I'm using `if((string)(int)$var == $var)` from the previous question. – Hamster Mar 11 '11 at 20:58

score 0 · Answer 2 · answered Mar 11 '11 at 20:24

0

Maybe try is_numeric. According to the examples in the documentation, this is exactly what you want.

answered Mar 11 '11 at 20:24

krtek

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While `is_numeric` works on strings, it also returns true for things that convert into floats. – Charles Mar 11 '11 at 20:25

score 0 · Answer 3 · answered Mar 11 '11 at 20:24

0

Could you use is_int in conjunction with is_string?

For example:

if(is_int(x) == 0 && is_string(x))

answered Mar 11 '11 at 20:24

user387049

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No. A variable cannot be of type string and of type int at the same time. The expression you quote is true if `x` is a string and false otherwise—not at all what the OP asked for. – Jun 20 '11 at 13:01

score 0 · Answer 4 · edited Aug 14 '12 at 23:47

0

$input =  preg_match("/^[0-9]{1,}$/",$input) ? (int)$input:$input;

edited Aug 14 '12 at 23:47

answered Mar 11 '11 at 20:29

matt

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\d matches decimal digits. http://www.php.net/manual/en/regexp.reference.escape.php \d is the same thing as [0-9] – Jun 20 '11 at 13:06

score 0 · Answer 5 · answered Jun 20 '11 at 13:05

0

Same answer as matt but easier to read:

preg_match('/^\d+$/', $x)

But ctype is probably faster if your system has it.

answered Jun 20 '11 at 13:05

I want my form input as an integer... but only if it was submitted as such

5 Answers5