Question

raise NoSuchStrategyError unless some_string1[1] + some_string2[1] =~ /[RSP]{2}/i

I do not get the “=~ /[RSP]{2}/i” part.

If you guys have time to answer, I’d appreciate the help.

I mean what does =~ do in there?

What does “/ /i” do in there?

I have a guess that /[RSP]{2}/i produces all possible pairs out of [RSP]. Is that true? Why do we need / /i then? Why doesn’t it produce pairs in irb, when I type /[RSP]{2}/i all I get from irb is

=> /[RSP]{2}/i 

and not pairs.

Answer 1

It’s a shortcut for regex (regular expression) match. It does not produce any pairs.

=~ operator means “does left-hand value match right-hand regex?”

/[RSP]{2}/ is a regex literal. You can write it instead of Regex.new("[RSP]{2}")

And, finally, trailing /i in regex literal means that this regex should be case-insensitive.