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need help with a script that should replace last x digits of a number with "x", it does all but the last x

Posted on 2008-06-25
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Last Modified: 2011-10-19
Hi

I have the function attached that takes a string (card number) and should turn the last x digits into "x" to obscure the number. It almost works but turns the last x into "x", it should be everything BUT the last x.

Example: 1234 5678 1234 5678
is becoming 1234 5678 12xx xxxx
it should be xxxx xx34 1234 5678
/**

	* returns part of the parameter

	*	

	* @param string $cardNumber

	* @return	string $safeNumber

	* @access	private

	*/

	private function safeNumber($cardNumber) {	

		$safeNumber = "";

		$char = "x";

		$numToHide = 6;		

		$cardNumber = substr($cardNumber, 0, strlen($cardNumber) - $numToHide);		

		for ($i = 0; $i < $numToHide; $i++) {

				$cardNumber .= $char;

		}			

		for ($startPos = 0; $startPos <= strlen($cardNumber); $startPos+=4)	{

			$safeNumber .= substr($cardNumber, $startPos, 4) . " ";

		}

		return $safeNumber;

	}

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Question by:NeilT
  • 2
  • 2
  • 2
  • +2
8 Comments
 
LVL 6

Accepted Solution

by:
Iced-evil earned 500 total points
ID: 21865202
modify this :

$cardNumber = substr($cardNumber, 0, strlen($cardNumber) - $numToHide);            
            for ($i = 0; $i < $numToHide; $i++) {
                        $cardNumber .= $char;
            }                  


into


$cardNumber = substr($cardNumber, $numToHide, strlen($cardNumber));            
            for ($i = 0; $i < $numToHide; $i++) {
                        $cardNumber = $char . $cardNumber;
            }                  
0
 
LVL 9

Expert Comment

by:Rob Siklos
ID: 21865223
This should work:
<?

private function safeNumber($cardNumber) {      

        $safeNumber = "";

        $char = "x";

        $numToHide = 6;         
 

        $numDone = 0;

        

        for ($i = 0; $i < $strlen($cardNumber); $i++) {

            $currChar = substr($cardNumber, $i, 1);

            if (($currChar == ' ') || $numDone > $numToHide) {

                $safeNumber .= $currChar;

            }

            else {

                $safeNumber .= $char;

            }

        }
 

        return $safeNumber;

}

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0
 
LVL 9

Expert Comment

by:Rob Siklos
ID: 21865226
shoot - ignore the last one - use this:
<?

private function safeNumber($cardNumber) {      

        $safeNumber = "";

        $char = "x";

        $numToHide = 6;         
 

        $numDone = 0;

        

        for ($i = 0; $i < $strlen($cardNumber); $i++) {

            $currChar = substr($cardNumber, $i, 1);

            if (($currChar == ' ') || $numDone > $numToHide) {

                $safeNumber .= $currChar;

            }

            else {

                $safeNumber .= $char;

                $numDone++;

            }

        }
 

        return $safeNumber;

}

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0
 
LVL 3

Author Closing Comment

by:NeilT
ID: 31470542
Thanks all, this worked!
0
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LVL 7

Expert Comment

by:dineesh
ID: 21865303
HI Can i recommend a simpler way,

i dont know javascript so have sent a sample in excel, you have to try the same logic in js

=REPT(B3,B2)&RIGHT(B1,LEN(B1)-B2)
safecard.xls
0
 
LVL 2

Expert Comment

by:HengTime
ID: 21865357
i would replace this:

  $cardNumber = substr($cardNumber, 0, strlen($cardNumber) - $numToHide);        
                for ($i = 0; $i < $numToHide; $i++) {
                                $cardNumber .= $char;
                }                      
                for ($startPos = 0; $startPos <= strlen($cardNumber); $startPos+=4)     {
                        $safeNumber .= substr($cardNumber, $startPos, 4) . " ";
                }

with this

$cardNumber = substr($cardNumber, $numToHide );  
$safeNumber = str_repeat("x",$numToHide).$cardNumber;
0
 
LVL 3

Author Comment

by:NeilT
ID: 21865421
Many thanks, all useful comments for me to take worward as I progress and look back over the code to clean it.
0
 
LVL 7

Expert Comment

by:dineesh
ID: 21865521
oops sorry,
i missed the fact that it was php code,  i dont know that either...
0

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