Regular expressions are a very useful tool for a variety of string related tasks.
In Kettle they are frequently used for extraction and manipulation tasks, as well as for specifying groups of file names.
The download package contains many samples of how to use regular expressions within PDI.
Let’s start with a basic question that may present itself if you’ve never worked with regular expressions before.
But if you take your time to read the carefully-built tables on the quick-launch page then perhaps the page about Get ready, because as far as I know, this site is one of the two most comprehensive regex sources on the net—along with Jan Goyvaerts excellent regex tutorial site.
In many regex flavors, you can aerate your regex just like code, indenting and inserting comments as you go.
Rex Egg tries to present regular expressions a bit differently, in the hope that these different angles help many people become more grounded in their knowledge of regex.
If you are looking for a drawn-out primer, this is not the place, as I don't see the need to pollute our beautiful world wide web with another explanation of how to match "foo" in "foo bar".
On an abstract level a regular expression, regex for short, is a representation of a set of strings. Instead of having a list and thus the complete set of strings that are valid zip codes, it’s often more practical to have a short and precise regex that completely describes the set. As an example consider the set of strings that end in “.csv”.
The following is a regular expression pattern that represents this set.