>>983223>[a-zA-Z0-9]*This matches any combination of those characters (including a zero-length string), so e.g. it will match AAA333aaa333
>[a-zA-Z][a-zA-Z0-9]*This will match a string starting with the first set of characters, so it won't match 3A (because it doesn't start with a character in [a-zA-Z]), after that it's the same as the previous one
>[a-z][^ ]*This matches a string starting with [a-z], followed by any number (including zero) of non-space characters. So it matches "a", "m", "a32m.2/", "m,,,,,,,," etc. But it doesn't match "3m" or "Am" because those don't start with [a-z].
