1. Regexp.union
Have a bunch of regex’s, and want to see if a string matches any of them, but don’t actually care which one it matches, just if it matches any one or more? Don’t loop through them, combine them with Regexp.union.
union_re = Regexp.union(re1, re2, re3, as_many_as_you_want) str =~ union_re
2. Regexp.escape
Have an arbitrary string that you want to embed in a regex, interpreted as a literal? Might it include regex special chars that you want interpreted as literals instead? Why even think about whether it might or not, just escape it, always.
val = 'Section 19.2 + [Something else]'
re = /key: #{Regexp.escape val}/
Yep, you can use #{} string interpolation in a regex literal, just like a double quoted string.
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