Understanding Ruby match method of Regexp class

Question

I was reading about the match method in ruby, I understood most of the example given at Regexp

But I am failing to understand, why is:

/[0-9a-f]/.match('9f')
=> #<MatchData "9">

And not:

=> #<MatchData "9f">

I might be missing some basic understanding of Regex, so bear with me.

Answer 1

Because you're asking it to match a single character of class 0-9 or a-f.

If you want to match multiple use a plus or an asterisk after the character classes e.g. /[0-9a-f]+/.match('9f')

It's all here.