Php only numbers Validating function

Question

I would like to create a validate function for numbers only, actually I have those ones that works fine, and I tried to create one myself, but it's unfortunately not working. Here are the alphanumeric and others working fine :

// Validators
private function custom($validator, $value)
{
    return call_user_func($validator, $value, $this->request, $this->id);
}

private function alphanumeric($value, $custom)
{
    return preg_match('/^(['.$custom.'a-z0-9_]*)$/i', $value);
}

private function valid_email($value)
{
    return preg_match('/^\S+@\S+\.\S+$/', $value);
}

And the one I tried to create by modifying the alphanumeric one :

private function numbers_only($value, $custom)
{
    return preg_match('/^(['.$custom.'0-9_]*)$/i', $value);
}

What's wrong with this one ?

EDIT : I also have a JS helping with the form, for alphanumeric it's :

Form.prototype.alphanumeric = function(value, custom)
{
    return !value.replace(new RegExp('['+custom+'a-z0-9_]', 'ig'), '').length;
};

What would be the JS for numeric only ?

use the D flag unless you want to allow a trailing new line. — goat
– goat, Commented May 11, 2012 at 12:47

Johannes Klauß · Accepted Answer · 2012-05-11 12:47:24Z

15

Use

is_numeric($value);

return is true or false

answered May 11, 2012 at 12:47

Johannes Klauß

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1 Comment

Michael Berkowski Over a year ago

Use caution with is_numeric(). Things like scientific notation 1e4 will return true.

Michael Berkowski · Accepted Answer · 2012-05-11 12:50:10Z

7

If you want only numbers, remove the $custom part from the function. The /i implies case-insensitive matching, which is not relevant for numeric matches, and so can be removed.

private function numbers_only($value)
{
    return preg_match('/^([0-9]*)$/', $value);
}

The expression above will match zero or more numbers, so blank input is allowed. To require at least one number, change * to + as in

return preg_match('/^([0-9]+)$/', $value);

And the [0-9]+ can be abbreviated as \d+. Since you are not capturing the value inside a an array of matches, there is no need for the extra overhead which is added by including the () capture group. That can be omitted as well.

return preg_match('/^\d+$/', $value);

Or skip the regex entirely...

Finally, if you've gotten this far and are matching only integers, it is far easier and less resource-intensive to just do:

// If you really intend to match numbers only, and not all numeric values
// which might include .,
function numbers_only($value)
{
  return ctype_digit(strval($value));
}

edited May 11, 2012 at 12:50

answered May 11, 2012 at 12:44

Michael Berkowski

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2 Comments

pimarc Over a year ago

What would be the JS corresponding to ctype_digit ?

Michael Berkowski Over a year ago

@Jamescoo Don't think there is one. In JavaScript, regex is usually used.

Zauker · Accepted Answer · 2019-04-05 09:21:50Z

5

In PHP, for a "only numbers" validation you can use different approaches:

is_int or is_integer
is_numeric
regular expressions
ctype_digit
filter_var

is_integer()

for this function these values are are not valid: "0010", "123"

is_numeric()

for this function these values are valid: 1.3, +1234e44 and 0x539

filter_var()

for this function a value as "00123" is not valid

CONSLUSION

it seems that only regex and ctype_digit work always fine.

TEST

a simple test here

answered Apr 5, 2019 at 9:21

Zauker

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Or skip the regex entirely...

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Or skip the regex entirely...

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