regexp is a function by far I have used the most to work on the string-related Cody problems, which I have spent a lot of time trying to understand how it works and yet a lot of questions still remain. There is an example in doc regexp under Dynamic Regular Expressions (modified below)
a = 'zzabcbagh';
This is to "find palindromes that are at least four characters long". What I don't understand here is why the two '.' (dots) are necessary. How about the first '?'
Besides, when 'once' is used, it returns as char; however, when it is igored ('all' by default), it returns as cell. Why?
Thank you in advance.