how to check that a variable has only numerical values and not text inside?

marcnyc

Hi, I have a little difficulty getting this condition together...

I have a variable $var that will assume any value (characters and numbers) but that has to have a value (required) and a variable $n that also will assume any value and has to have a value (required). I need to build a condition that will do a certain thing ONLY if $var does NOT have and $n has any value that is not a number (in particular between 1 and 50). In other words if $var has any value and $n has any NUMERICAL value then it's ok but if either $var has no value or $n has a value that is NOT numberical then it is not ok.

I tried this:

if ( !$var && $n >= "1" && $n <= "50" ) {
not ok
} else {
it's ok
}

but it doesn't work.

Can somebody help me?

DeadlySin3

You can use gettype() to test the type of any variable.

<?php

$var; // declaring w/o assigning
echo gettype( $var ); // returns null
echo "<br />";

$var = 5;
echo gettype( $var ); // integer
echo "<br />";

$var = "five";
echo gettype( $var ); // string
echo( "<br />");

$var = 5.0;
echo gettype( $var ); // double
echo( "<br />"); 

$var = true;
echo gettype( $var ); // boolean
echo "<br />";

?>

you can use settype() to make sure it's the type of var you want it to be.

$var = 3.14; // pi ;p
echo gettype( $var ); // returns double
echo " is $var<br />"; // 3.14
settype( $var, 'integer' );
echo gettype( $var ); // now an integer.

I don't know if thats what you were looking for or not. Either way, i hope it helps ya out!

Weedpacket

First of all, see [man]is_numeric[/man].

Second, I'll just paraphrase your condition:

In yet other words; if(!empty($var) && is_numeric($n)){
ok
}else
not ok
}

marcnyc

Thanks to the both of you... Don't know grettype() but it seems like is_numeric() is exactly what I am looking for because I need to make sure that the value is numeric...

I tested it like this:

if (!$var || !is_numeric($n))

and it worked perfectly...

Now I only have one doubt/question/curiosity... is there a difference between my syntax (!$var) and yours (!empty($var))? Is mine wrong? Are they the same thing or are there differences?

Weedpacket

The only significant difference is that empty($var) won't cause a warning about an "uninitialised variable" if $var happens to not be set. It won't make a difference if error reporting is set leniently enough.

krylor

Hi ,

The function below returns a string "0" if ur string is not a valid
number .

It also works for decimal numbers.

Hope this is what you were looking for

regds

<?
function snum($data)
{
$str = trim($data);
$length = strlen($str);
$isdot = false;
$flag = true ;
if ($length == 0) $flag = false;

for ($i = 0 ; $i < $length && $flag ; $i++ )
{

  if (  ( substr($str,$i,1) <= "9" && substr($str,$i,1) >= "0" ) ||  ( substr($str,$i,1) == "." && !$isdot ) )
  {
     if ( substr($str,$i,1) == "." ) $isdot = true;
  }
  else
  {
     $flag = false;
  };

};

if ($flag)
{
return($str);
}
else
{
return("0");
};

};

Weedpacket

krylor: how is your function snum($data) different from is_numeric($data) ? $data : "0"?

krylor

well not much different .
Its actually a port of something i wrote in javascript
and i also read somewhere that isnumeric in php has a limitation
of some no of digits

Weedpacket

Originally posted by krylor
well not much different .
Its actually a port of something i wrote in javascript
and i also read somewhere that isnumeric in php has a limitation
of some no of digits

Ah, probably limited to numbers that can actually be stored in a numeric variable type.

preg_match("/^[\d.]+$/",$data) && substr_count($data,'.')<=1;

...could probably be ported to Javascript...