A simple search/strip out question

spaced

I am trying to teach myself the best way to do this, but I am kind of stumped.

I have a string, for example:

$startstr="10675,g10705,4668,9983,10710,7929,g1082,10163";

What I want to do is strip out any entry prefixed with a "g" and ending with the subsequent comma and put it in a new string.

For instance:

$newstring1="10675,4668,9983,10710,7929,10163";

would have all the entries stripped out, and another string:

$newstring2="g10705,g1082";

would have just the "g" related entries.

I know this is kind of trivial, but I have been playing around with preg_replace and preg_match_all and I can't get them to work out as I thought they would.

Thanks in advance for any help!!!

laserlight

What do you mean by "strip out"?

spaced

Originally posted by laserlight
What do you mean by "strip out"?

I mean take some matches in a string, remove them, and put them in another string. So the end result is I have two new strings, one with the found matches removed, the other with the found matches only.

laserlight

Here's an example:

function partitionStr($str, &$new_str, &$stripped_str, $prefix = 'g') {
	//split comma delimited string into array
	$temp = explode(',', $str);
	//define 2 local arrays
	$new_str_array = array();
	$stripped_str_array = array();
	//loop through array and test for the prefix
	foreach ($temp as $temp_str) {
		if ($temp_str{0} == $prefix)
			$new_str_array[] = $temp_str;
		else
			$stripped_str_array[] = $temp_str;
	}
	//join the local array elements into the strings passed by reference
	$new_str = implode(',', $new_str_array);
	$stripped_str = implode(',', $stripped_str_array);
}

My idea is to change the string into an array.
We then test each string element in this array, to see if it has the required prefix.
If it does, we then place it into a another array.
Otherwise, we then place it into yet another array.

These extra arrays have their elements joined back, using commas as the glue.

Of course, a faster alternative would be to append to the strings directly, but then you'll have to deal with a trailing comma.

spaced

laserlight, that works wonderfully. The way I was trying to make it work was to somehow do a preg_match_all, get all the matches, and then do a preg_replace and replace all the "g" entries with a "", but like I said before I couldn't get it to work. Thanks again!