ruby match regular expression

Question

I'm trying to require all the files in a folder. I have the following.

    Dir.foreach File.expand_path("app/models") do |file|
        require file unless file === /^\./
    end

However, it's failing. When I open up a ruby console, I try the following:

"." === /^\./

and it evaluates to false. Why won't it match?

That's just the way I've always done regex matching. I didn't realize that I had the operands flipped around though. — Hugo, Aug 17 '14 at 22:54
That's perhaps an argument for using `=~`, as order makes no difference: `r = /^\./; ".ab" =~ r #=> 0; r =~ ".ab" #=> 0`. — Cary Swoveland, Aug 17 '14 at 23:51

Michael Berkowski · Accepted Answer · 2014-08-17T22:37:49.930

The === operator is actually a method of the object on the left.

The order of operands on the === matters in this case, because if the string literal "." comes first, the String equality operator (method) String#=== is evaluated. If the regex literal is placed on the left, the Regexp operator Regexp#=== is used:

Reverse your operands.

# The string "." isn't equal to the Regexp object
>> "." === /^\./
=> false

# With the regexp as the left operand:
>> /^\./ === "."
=> true

# With the string on the left, you may use =~ and test for nil as a non-match
>> "." =~ /^\./
=> 0

ruby match regular expression

1 Answers1