From: "Aaron D. Gifford" <astounding@...>
Date: 2011-04-07T02:52:00+09:00
Subject: String#each_*slice* methods (like Enumerable#each_slice)

Hi,

I find I periodically need to iterate over slices of a string.
Enumerable has the useful each_slice method, but in Ruby 1.9, I don't
see an equivalent for the String class.

So I've monkey-patched String a bit like this:



## Monkeypatch String to add some each_*slice* methods:
class String
  ## Like Enumerable#each_slice() only it yields a string
  ## of chars characters (the slice):
  def each_slice(chars)
    self.scan(/.{1,#{chars}}/m).each do |s|
      yield s
    end
  end

  ## Like Enumerable#each_slice() only it yields an array
  ## of Fixnum bytes from the string (the slice):
  def each_byteslice(bytes)
    self.bytes.to_a.each_slice(bytes) do |s|
      yield s
    end
  end

  ## Like Enumerable#each_slice() only it yields a binary
  ## string of specified bytes (the slice):
  def each_bslice(bytes)
    if encoding == Encoding::BINARY
      str = self
    else
      str = self.dup.force_encoding(Encoding::BINARY)
    end
    str.scan(/.{1,#{bytes}}/m).each do |s|
      yield s
    end
  end

end



So now for the question.  Is there a better way to accomplish
something similar?  I'm not debating whether to do it as a monkey
patch or not--that's irrelevant to me. But is there a more efficient
way to slice up strings and iterate over fixed sized chunks?

One alternative each_bslice implementation I tried used
str.bytes.to_a.map(&:chr).each_slice(x){|c| p c.join} but it was a bit
slower in benchmarks versus the str.scan method.

Aaron out.