title: Clear every other bit in Ruby
body: <p>How do I clear every other for a string in Ruby, and convert it to byte array? I understand that I need to do AND operation with 0x01010101 value for every byte. But the difficulty is with correct conversion from string to binary. Ideally it should be fast and with least amount of allocations.</p>
  
  <p>Later I will need to pass this value to <code>Digest::MD5.hexdigest</code>.</p>