Comment by refactor_master

> Despite being clean and readable, I don't tend to do it any more, because it's harder to debug. More often these days, I write things like this:

    data = File.readlines("haystack.txt")
    data = data.map(&:strip)
    data = data.grep(/needle/)
    data = data.map { |i| i.gsub('foo', 'bar') }
    data = data.map { |i| File.readlines(i).count }

Hard disagree. It's less readable, the intend is unclear (where does it end?), and the variables are rewritten on every step and everything is named "data" (and please don't call them data_1, data_2, ...) so now you have to run a debugger to figure out what even is going on, rather than just... reading the code.