check if variable is number, decimal, positive/negative

[2000a]

Hi,

 

How can I check if a variable only has these characters:

- number (0-9)

- decimal point (.)

- positive (+)

- negative (-)

- dollar ($)

 

I tried is_numeric, but it doesn't like negative values...

 

I need to add the variable value to another variable. I have to accept numbers (including negative and decimals)...

 

ex:

0.1 = TRUE

-.1 = TRUE

12 = TRUE

1000.00 = TRUE

12a = FALSE

 

 

 

thanks

[The Little Guy]

You could do it this way (I wasn't sure if spaces were allowed so I added them to the array):

<?php
function is_good($str){
$allowed = array('0','1','2','3','4','5','6','7','8','9', '.', '+','-', '$', ' ');
$arr = str_split($str);
foreach($arr as $itm){
	$itm = (string)$itm;
	if(!in_array($itm, $allowed, true))
		return false;
}
return true;
}

$str = '$12 + 12.01 -.01';
if(is_good($str)){
echo 'good';
}else{
echo 'bad';
}
?>

[2000a]

thanks The Little Guy.

 

Is there a way to do it on one line?

 

I have this working with the exception of negative+positive values (ignore the $):

if(ereg("^[.0-9]+$", $myVar)) { return TRUE; }

 

If I add "\-" it still doesn't like "-"..

 

So if myVar="-.01", I want it to return TRUE.

 

 

thanks

 

[berridgeab]

As this is the 3rd result in the google search results, I thought I'd post the answer I found lurking on some other website.

 

To validate a True Decimal Number.

 

//if the number is not a whole number then its a decimal.
function validateTrueDecimal($v) 
{	return(floor($v) != $v);		}


//A Small Unit Test
$test = array (0.5, 0.12, 0.56, 1, 10, "Apples", -13.4, -5.12178934123487123491912471249124, 1e7, "1e7", "1.2");

foreach($test as $value)
{
if (validateTrueDecimal($value)==true) 
{ echo $value . " - Number is a decimal<br>";}
else 
{echo $value . " - <b>Number is not a decimal</b><br>";}
}	

 

Output of Code -

0.5 - Number is a decimal

0.12 - Number is a decimal

0.56 - Number is a decimal

1 - Number is not a decimal

10 - Number is not a decimal

Apples - Number is not a decimal

-13.4 - Number is a decimal

-5.1217893412349 - Number is a decimal

10000000 - Number is not a decimal

1e7 - Number is not a decimal

1.2 - Number is a decimal

[berridgeab]

Scrap the above, further testing shows it doesn't work on 10.00, 20.00, 30.00, 1.00, etc. Back to the drawing board....

[litebearer]

The "sledge-hammer" approach...

<?PHP
$os = "abc $ 123.4 + - wowoow#";

function CheckThisNumber($os) {
/* first remove all invalid characters */
$string = preg_replace("/[^0-9\|\.\-\+\$]/", "", $os);
/* next compare original to new - if not the same then bad */
if($string != $os) {
	return FALSE;
}
/* count the occurrences of +, -, . and $ */
$c_minus = substr_count($os,"-");
$c_plus = substr_count($os,"+");
$c_dec = substr_count($os,".");
$c_dollar =substr_count($os,"$");

/* if there are both - and + then bad */
if($c_minus>0 AND $c_plus>0) {
	return FALSE;
}

/* if there are more than one occurrance of + or - or . or $ then bad */
if($c_minus>1 OR $c_plus>1 OR $c_dec>1 OR $c_dollar>1) {
	return FALSE;
}

/* there is a + or -  AND it is NOT the first character then bad */
if(($c_minus==1 and $os[0] !="-") OR ($c_plus==1 and $os[0] !="+")) {
	return FALSE;
}
/* if there is a - or + AND there is a $ AND the $ is not the 2nd character then bad */
if(($c_minus==1 and $c_dollar==1 and $os[1] !="$") OR ($c_plus==1 and $c_dollar==1 and $os[1] !="$")) {
	return FALSE;
}

/* if there is NO - AND NO + BUT there is a $ AND the $ is not the 1st character then bad */

if($c_minus<1 and $c_plus<1 and $c_dollar ==1 and $os[0] !="$") {
	return FALSE;
}

return TRUE;
}
echo $os . "<br>";
if(!CheckThisNumber($os)) {
echo "BAD";
}else{
echo "GOOD";
}
echo "<br>";
$os = "-$1234.56";
echo $os . "<br>";
if(!CheckThisNumber($os)) {
echo "BAD";
}else{
echo "GOOD";
}
echo "<br>";
$os = "$-1234.56";
echo $os . "<br>";
if(!CheckThisNumber($os)) {
echo "BAD";
}else{
echo "GOOD";
}
echo "<br>";
$os = "-$$1234.56";
echo $os . "<br>";
if(!CheckThisNumber($os)) {
echo "BAD";
}else{
echo "GOOD";
}

?>

[Vander]

I've just done a wee modifcation of the code berridgeab was working on, it seems to be working a bit better than his, and might be able to help you out as well.

 

<?php
$test = array (+0.5, 0.12, 0.56, 1, 10, "Apples", -13.4, -5.12178934123487123491912471249124, 1e7, "1e7","$654.43","$4,324.43", "1s7", "1.2");
foreach($test as $value):
if(substr($value,0,1) == '$'):
	$value = substr($value,1);
endif;
$value = str_replace(',','',$value);
$oldvalue = $value;
if(!is_numeric($value)):
	settype($value,'float');
endif;
if($value === $oldvalue):
	echo "{$oldvalue} - Number is a decimal<br>";
else:
	echo "{$oldvalue} - Number is NOT a decimal<br>";
endif;
endforeach;
?>

 

And it returns the following.

 

0.5 - Number is a decimal
0.12 - Number is a decimal
0.56 - Number is a decimal
1 - Number is a decimal
10 - Number is a decimal
Apples - Number is NOT a decimal
-13.4 - Number is a decimal
-5.1217893412349 - Number is a decimal
10000000 - Number is a decimal
1e7 - Number is a decimal
654.43 - Number is a decimal
4324.43 - Number is a decimal
1s7 - Number is NOT a decimal
1.2 - Number is a decimal

 

Edit: I refined it a little to accept "$" and commas, the only reason 1e7 seems to be accepted, is 'cause it's the same as "10,000,000".