This post gives an introduction to regular expressions in general as well as some applications within Kettle a.k.a. Since the built-in Kettle steps use the Java regular expression engine, the samples in this post will be notated to work with the Java implementation of regular expressions.
The article contains many samples to explain each concept encountered in regular expression syntax.
What are then the characters that do have special meaning?
The following list shows the characters that have special meaning in a regular expression, and must therefore be escaped by a backslash character if they are supposed to be processed as literal characters.
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.
This post explains the basics of regular expressions and provides samples for many PDI features that support them in the download package.
Consequently PDI supports regular expressions in many places.
There are several steps dealing with string validation and manipulation.
Sometimes it’s necessary to refer to some non-printable (or not-easily-typed) special character.
The following table gives the notation details for common special characters, as listed by the Java documentation.
The download package contains many samples of how to use regular expressions within PDI.