string manipulation (!!!!)

[Anon]

Lets say I have a string:

$msgBody = "This is\na message\n\n

preserve\n    whitespace

\n\ntest

preserve\n\n\nthis whitespace\n       also

";

now what I want to do is replace all whitespace characters between

 and 

with an underscore character. Also, the number of

 and 

tags can vary within the string, sometimes there could be only 1, another time there could be 50.

How would I go about doing this, it's really driving me nuts!

Thanks for any help anybody can give me!

[Anon]

Ok, it ain't pretty, but it works.

<?php

$msgBody = 'This is a

 test for white 

space blah blah

 more text over here

blah blah';

$inCode = false; // are we in

 tags?
$newString = ""; // string we're building
$msgLength = strlen($msgBody); // how many char's are we searching through?

for ($i = 0; $i < $msgLength; $i++)
{
  // check to see if we're starting code block
  // NOTE: not case sensitive
  if (substr($msgBody, $i, 6) == "[code]")
    {
      $inCode = true;
      $newString .= "[code]"; // throw the '[code]' string in and save some unnecessary additional parsing
      $i += 6; // increment the counter by the length of the char's we just appended
      continue; // go to the next char
    }
  if ($inCode)
    {
      // check to see if we should stop searching for whitespace
      if (substr($msgBody, $i, 7) == "

")
{
$inCode = false;
$newString .= "[/code]";
$i += 7;
continue;
}
// if we hit here, we're in a code block and have to check for whitespace
$newString .= ($msgBody{$i} == " ") ? "" : "$msgBody[$i]"; // if it's a space, append
// if it's not, append the character as is
}
else
{
// if we get here, we're not in a code block, so just append as is
$newString .= $msgBody{$i};
}
}

echo "$msgBody<BR>";
echo "$newString";

?>

NOTES:
1. This only searches for a space, " " NOT all whitespace as you specified.
2. The search for the

 block is case sensitive as the comment mentions.  [CODE] or [CoDe] will not cause it to start replacing spaces.

Hope this helps a little anyway.

Adam

[madmada]

Sorry, missed a few things in the previous post in my haste.

The comment in the code:

// NOTE: not case sensitive

is wrong. It should state that it IS case sensitive.

Secondly, regarding indexing into a string. The php.net manual regarding strings says to use the {} for indexing instead of [] as that is deprecated. (See example 6-3 here: http://www.php.net/manual/en/language.types.string.php
I tested this code on PHP 4.0.3pl1 and it didn't understand {} indexes, only []. So you may want to try using {} and see if your version supports it as [] are supposedly deprecated since PHP4.

Quote from aforementioned page:

"String access by character
Characters within strings may be accessed by specifying the zero-based offset of the desired character after the string in curly braces.

Note: For backwards compatibility, you can still use the array-braces. However, this syntax is deprecated as of PHP 4."

Adam

[madmada]

Last one, I promise!

The value to increment $i after appending

 or 

to the new string should be 5 and 6 respectively, not 6 and 7. I forgot $i is incremented automatically when the for loop continues. As it is, it drops the character immediately following the

 or 

sub strings.

My apologies.

Adam