PHP Regex - Value of 1 or more integers

php regex input validation

17,760

Solution 1

Try this regexp:

/^\d+$/

The issue with your existing regexp is that it only matches strings with exactly one digit.

As for validating an int or a double:

/^\d+\.?\d*$/

Note that that regexp requires that there be at least one digit.

Solution 2

Use:

/^[0-9]+$/

The + means "one or more". Without it, your regex will only match a single digit. Or you could use the simpler variant:

/^\d+$/

For floats, try something like:

/^\d+(\.\d{1,2})?/

This will match one or more digits, optionally followed by a . and one or two digits. (i.e. .12 will not match.)

To save yourself some headaches, you can also use the is_int and is_float functions.

Lastly; note that your check is wrong. preg_match will return 0 if it fails, so you should write it as:

if (!preg_match("/^\+$/", $original_stock)) {
  // error
}

(note the !).

Solution 3

You may want to use the

is_int

Solution 4

Don't reinvent a wheel slower than an existing one, use a motorcycle: is_int.

#Assuming $original_stock is a single value...
if (is_int($original_stock)) {
    #Valid, do stuff
}
else {
    #Invalid, do stuff
}

#Assuming $original_stock is an array...
$valid = true;
foreach ($original_stock as $s) {
    if (!is_int($s)) {
        $valid = false;
        break;
    }
}
if ($valid) {...}
else {...}

Solution 5

I just ran into this exact problem and solved it this way using the regex.
I think the problem is your caret ^.

/^[0-9]$/

I moved it inside the class and got the results I needed.

function validate_int($subject)
{
    //Pattern is numbers
    //if it matches anything but numbers, we want a fail
    $pattern = '/[^0-9]/'; 
    $matches = preg_match($pattern, $subject);
    if($matches > 0)
      return false;
    else
      return true;
  }

View more solutions

17,760

Author by

JheeBz

Updated on July 18, 2022

Comments

JheeBz almost 2 years
Hey I'm trying to perform input validation in PHP to ensure that the stock values that are typed in are at least 1 positive integer and from 0-9. Should not contain any special characters.

For example, any of the following values should be valid:
```
7
0
32
47534
```
The following SHOULD NOT be valid:
```
asdf
35/gdf
../34.

etc..
```
I'm using the following if statement to check for the positive integer value of "$original_stock".
```
if (preg_match("/^[0-9]$/", $original_stock)) 
{
    $error .="Original stock must be numerical.";
}
```
Additionally, I have a price field which should be validated as either an int or a double.

If there's an easier alternative to using regex, that's okay too!

Thanks in advance :)
JheeBz almost 13 years

I tried the first and the second one but if the input is "30" then it causes an error either way.
Mat almost 13 years

what do you mean "causes an error"? note that these regex require that there is nothing else than the number - no whitespace in particular.
JheeBz almost 13 years

It does not match using the "preg_match" function and thus assigns a string to the $error variable. The number does not have any whitespace or anything by the way. It's just 30 and was taken straight from the database.
Mat almost 13 years

Edited my answer. The match works, you're not testing it correctly though.
Alix Axel almost 13 years

is_int wont do it if the input comes from a form, only is_numeric. Either way, you are also validating negative integers and possibly non-integers.