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Comment by djacobs | Hacker News Reader

I don't think so, select is just a filter. List comprehensions map and select at the same time.

Regarding TLDMs, how do you propose mapping a TLDM over an array? For example:

  def transform(x)
    # implementation ...
  end

  list = [1, 2, 3]

  # doesn't work ...
  list.map &transform

Edit: &method(:transform) is way too verbose compared with Python's solution

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    def transform(x)
      x * 2
    end
    
    list = [1, 2, 3]
    
    p list.map &method(:transform)

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You wouldn't use a named Ruby method for something like this. You'd typically use a Proc or block.

    [1,2,3].map{ |x| x * 2 }

or if you wanted to reuse the block for other things

    transform = lambda { |x| x * 2 }
    [1,2,3].map(&transform)

Exactly, but there should be an easier syntax that declaring a lambda for each algorithm I want to map over.

That's probably why explicitly calling transform inside the block, or making transform a method of the objects you're trying to transform, is more idiomatic Ruby.

You're right in that list comprehensions are semantically equivalent to combining map and select, not just select.

    alias :m :method

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