Regex tutorial / construction site that can be used in Knime

Hi Knimers,

In my work, I have to use regex a lot, but I do not know how to construct regex which can be used in Knime. Can anyone of you point me in the direction of regex tutorial or construction website which works readily once I prepare it in that site. I tried couple of sites but they are not readily implementable in Knime directly.

I know this is really not a knime related query directly but many of you may be already using it to construct the regex using some sites. Hence, requesting for help.

Best,