Supposedly my string is:
$a = 'abc-def";
i only want a-z in my string.
but i want to let the user know what "bad" character makes their string "bad".
i can do this:
$conflict = preg_replace('/[a-zA-Z0-9 .]/', '', $a);
echo "the conflict was: $conflict";
but if my string is huge.. let's say a document filled with lots of text.. then this code above would go through the entire document and show all the conflicting characters.
i would like it to STOP after it finds only 1 conflicting character.
that way less CPU / memory / resources are used.
in other words.
$a = 'abc-,def";
in this example it should stop and indicate the conflict is "-"
rather than report the conflict is : "-,"
because soon as it sees "-" it should stop looking anymore.
the goal is to not use too many resources.
MORE INFO:
the idea is to read a string from left to right (i suppose) and soon as a character is detected that does not obey the law of a-z and 0-9.. the process is to be terminated and the string that has been found is to be reported
You can do the following:
if (preg_match("/[^a-z0-9]/i", $a, $match)) :
echo "Conflict was: $match[0]";
Logic: Check for characters other than a-z0-9 and if there is a match print the response.