PHP validation function. Check for numeric and positive

Question

Little confused about how to code this. User inputs numbers, then the validation checks to make sure it is numeric and positive. The user can also leave this field blank.

This is what i have so far, it just checks to see that something was inserted.

$error_blue = check_blue($phone);
if($error_blue !=''){
    print "<p>Blue: $error_blue";
    }

Is where the item is validated at the top of the page.

function check_blue($blue){
if(! is_numeric($blue)){
    return'Please Enter a valid number for Blue.';
}}

Is where the function is. Any help on what to do here would be much appriciated.

Kermit · Accepted Answer · 2013-04-17 23:33:02Z

2

Something like this?

function check_blue($blue) {
    if (is_numeric($blue) && $blue > -1) {
        return 1;
    }
    else {
        return 0;
    }
}

if(!check_blue($phone)) {
    return'Please Enter a valid number for Blue.';
}

See the demo

answered Apr 17, 2013 at 23:33

Kermit

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1 Comment

Kermit Over a year ago

@user2168066 I don't follow.

dave · Accepted Answer · 2013-04-17 23:32:21Z

0

Assuming it's an integer you expect,

if ((int)$blue==abs($blue) || empty($blue)) $error = false;
else $error = true;

Then you use $error to decide what to do.

answered Apr 17, 2013 at 23:32

dave

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Salvador Dali · Accepted Answer · 2013-04-17 23:35:14Z

0

Everyone here was using if else. It is not that this is wrong, but just to show you another idea, which might be useful for other type of validation, take a look at validate filters : http://www.php.net/manual/en/filter.filters.validate.php For this purpose you might use FILTER_VALIDATE_INT

answered Apr 17, 2013 at 23:35

Salvador Dali

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scones · Accepted Answer · 2013-04-18 00:26:39Z

0

You might want to use something simple as

function check_blue($phone) {
  return (empty($phone) || (is_numeric($phone) && $phone >= 0));
}

First check if the field is blank, nothing to do if it is. If it is not blank it will be checked for numericality and to being greater or equal zero.

answered Apr 18, 2013 at 0:26

scones

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