Dim word_query = _ (From word As String In words _ Order By word _ Select word). Write Line(" " & stra(i)) Next Dim lines() As String = IO. The most basic building block in a regular expression is a character a.k.a. Most characters in a regex pattern do not have a special meaning, they simply match themselves.
Consequently PDI supports regular expressions in many places.
There are several steps dealing with string validation and manipulation.
The need to escape every character as literal makes it harder to read and to understand.
If there are sequences of characters in a pattern that should be interpreted as literals, they can be enclosed by Groups, notated by round brackets, have several uses in regular expressions.
The mechanics of this particular pattern aside, a regex engine can test a pattern against an input string to see if it matches. If a particular problem seems to be very challenging however, it may help to revert to the abstract view that is used for reasoning about regular expressions.