great site. found it yesterday and read is nearly all. Good Job.
But I on the RegExp page you made a mistake on the [^af] pattern. It says the [^af]
Matches any character not being one of the provided between brackets [ ]
Then in the example column: [af] where it should be [^af] I guess.
and in the example match: “a”, “f” in “alfa” this should be “f” in “alfa”
If I interpret the pattern correctly.