Splitting and rebuilding a string

[victimist]

Hi,

I have spent the last 3 hours trying to split a string in php and rebuild it to shorten it. The outcome always failed ...

I am farmialir with VB, and have googled up how to code php ... But still i am unable to code a solution. i have tried using list, split_str, split, explode to no avail. (Prob due to the fact that my php skills are 0)

I have a pre-existing php which generates an arp table. Im trying to split a mac address variable then build a new string which only contains the 1st 3 values of the split mac address. The VB equivalent would look something like

====

strStartString = "xx:xx:xx:xx:xx:xx"
arrStartString = split(strStartString,":")

If len(arrStartString(0)) = 1 then
arrStartString(0) = "0" & arrStartString(0)
End If
If len(arrStartString(1)) = 1 then
arrStartString(1) = "0" & arrStartString(1)
End If
If len(arrStartString(2)) = 1 then
arrStartString(2) = "0" & arrStartString(2)
End If

newStrString = arrStartString(0) & arrStartString(1) & arrStartString(2)

====

Desired result being:
Mac1 = 0:55:00:F0:AB:CD
Result1 = 005500

Mac2 = 0:C:5:22:32:F4
Result2 = 000C05

Sorry for the NOOB question

Thank you

[mlseim]

PHP Code:

<?php

$strStartString = "xx:xx:xx:xx:xx:xx";
$pieces=explode(":",$strStartString);

// now it's an array.
// here is how to loop through the array and do things with each piece.

$build1="";
$build2="";
$count=0;
foreach($pieces as $piece){
   if(strlen($piece==1)){
   $piece="0".$piece;
   }
      if($count<= 2){
      $build1 .= $piece;
      }
      else{
      $build2 .= $piece;
      }
}
echo $build1."   ".$build2;

?>

[victimist]

Thank you very much mlseim.

Appreciate you pointing me in the right direction

Will give this a go today and post the outcome!


Seasons greetings to all!

[victimist]

This is sort of working ... But its not creating a shortened string as i would have liked



the 2nd from the top has added an extra Zero - which is bang on. 0:1c:df:11:65:53 became 001cdf116553

But the very next one down didnt do it? 0:13:8f:f3:3f:3c became 0138ff33f3c and not 00138ff33f3c

Also, the new string still contains all charaters, i would have liked 0:1c:df:11:65:53 to become 001CDF and 0:13:8f:f3:3f:3c to become 00138F

Is this possible?

Thanks Guys!

[victimist]

I have added a line to track the count and now i get a shorted string as desired. BUT, still no luck on adding a "0" to a single Character string?

$strStartString = $arpw_mac;
$pieces=explode(":",$strStartString);

// now it's an array.
// here is how to loop through the array and do things with each piece.

$build1="";
$build2="";
$count=0;
foreach($pieces as $piece){
   $count= $count+1;
   if(strlen($piece==1)){
   $piece="0".$piece;
   }
      if($count<= 3){
      $build1 .= $piece;
      }
      else{
      $build2 .= $piece;
      }
}

[BluePanther]

Originally Posted by victimist

I have added a line to track the count and now i get a shorted string as desired. BUT, still no luck on adding a "0" to a single Character string?

$strStartString = $arpw_mac;
$pieces=explode(":",$strStartString);

// now it's an array.
// here is how to loop through the array and do things with each piece.

$build1="";
$build2="";
$count=0;
foreach($pieces as $piece){
   $count= $count+1;
   if(strlen($piece==1)){
   $piece="0".$piece;
   }
      if($count<= 3){
      $build1 .= $piece;
      }
      else{
      $build2 .= $piece;
      }
}

Almost, just a misplaced bracket . But, you're using double the memory, and iterating more than needed.

My suggested solution:

PHP Code:

$strings = explode(':',$arpw_mac);
// Leave only the first 3 indexes
array_splice($strings,3);
// Initialise result string
$result = '';
// For all three indexes
foreach($strings as $string){
    if(strlen($string) == 1){
        $result .= '0';
    }
    $result .= $string;
} 


Not tested my solution, but should work as expected.

Edit: Decided to test it just in case, and it does work as expected

[victimist]

Thanks BluePanther - Thats working perfectly

Appreciate your help

[BluePanther]

Originally Posted by victimist

Thanks BluePanther - Thats working perfectly

Appreciate your help

No problem!

[kbluhm]

Just curious if you had to mod that solution at all. I can't see how it works as desired if the return value of array_splice() isn't being captured. That is also a smaller point as I would expect array_slice() to be used instead, along with proper parameters. Lastly, the 0 for each single-character parts is being appended to the end rather than prepended to the front as your example states.

PHP Code:

$mac_addr = '0:C:5:22:32:F4';

$parts = explode( ':', $mac_addr );
$parts = array_slice( $parts, 0, 3 );

foreach ( $parts as & $part )
{
    $part = str_pad( $part, 2, '0', STR_PAD_LEFT );
}

$mac_addr_sub = implode( '', $parts );

echo $mac_addr_sub; // 000C05 


[BluePanther]

Originally Posted by kbluhm

Just curious if you had to mod that solution at all. I can't see how it works as desired if the return value of array_splice() isn't being captured. That is also a smaller point as I would expect array_slice() to be used instead, along with proper parameters. Lastly, the 0 for each single-character parts is being appended to the end rather than prepended to the front as your example states.

PHP Code:

$mac_addr = '0:C:5:22:32:F4';

$parts = explode( ':', $mac_addr );
$parts = array_slice( $parts, 0, 3 );

foreach ( $parts as & $part )
{
    $part = str_pad( $part, 2, '0', STR_PAD_LEFT );
}

$mac_addr_sub = implode( '', $parts );

echo $mac_addr_sub; // 000C05 


Are you talking about my solution?

array_splice() returns the removed parts from the array - the parts after offset, for length (default 0), are removed then returned. We don't need them, so they can just go unassigned. I used splice over slice as it made sense to me - I won't be using the rest of the array so why not just get rid. Verified the parameters for array_splice() - only 2 parameters needed as the rest are optional, and the default values are what I want.

The 0 is being appended to the string just before the current array part, if it's required. It checks length of the current index, appends 0 to the string if needed, then appends the array index.

It works as expected:
http://codepad.org/c8d2pAgn