Difference in a one line block code between === and match? - ruby

Question

I have the following code example to check whether some elements in an array match or not the given regular expression:
["SELECT column1, column2 FROM table1, table2 WHERE column2='value';",
"SELECT * FROM Customers WHERE Last_Name='Smith';",
"SELECT * FROM Friends"].none? { |sql| /WHERE/i.match?(sql) }
# false
As you can see, I'm using match? just to see if both the receiver and the method parameter match. I'm not interested on the pros of using match as it's stated on the docs:
Returns a true or false indicates whether the regexp is matched or not without updating $~ and other related variables. If the second parameter is present, it specifies the position in the string to begin the search.
So, I could easily use === for that:
["SELECT column1, column2 FROM table1, table2 WHERE column2='value';",
"SELECT * FROM Customers WHERE Last_Name='Smith';",
"SELECT * FROM Friends"].none? { |sql| /WHERE/ === sql }
# false
Which returns the very same. Maybe isn't so common to use case equality for this kind of things, but that allows me to pass the regular expression as the none? parameter, and avoid opening the block, as I'm using Ruby 2.5+:
array.none?(/WHERE/) # false
And works pretty much the same (also the same for every enumerable predicate method):
array.any? { |sql| /WHERE/i.match?(sql) } # true
array.any? { |sql| /WHERE/ === sql } # true
array.any?(/WHERE/) # true
So, my question is; would it be the same for me, considering these cases to use === to check every string instance in the arrays match with the given regular expression? If so, I could replace them all to just pass the regular expression as the method (none?, any?) parameter.

Answer 1

The reason for Regexp#=== existing is primarily for use in case statements, like:
case (str)
when /WHERE/i
# ...
end
As internally that calls the === to check for matches. This is why you can do a lot of really wild things like:
case (str)
when String
when 0..20
when 'example'
when /text/
end
Among other things, all by virtue of the === comparison.
It's worth noting it's not intended to be used as you have. match? communicates quite clearly your intent, but === may be confusing as it looks a lot like == which indicates "comparison", but this is not any ordinary comparison.
The good news is Ruby allows using a regular expression directly with any? as well as an alternative like:
[
"SELECT column1, column2 FROM table1, table2 WHERE column2='value';",
"SELECT * FROM Customers WHERE Last_Name='Smith';",
"SELECT * FROM Friends"
].grep(/WHERE/i).any?
Where the grep method can take either a string or a regular expression.
The grep method is great for filtering, but if you just want to know if any of them match it's not as efficient as any?, so I'd use that instead.