Convert string with hex ASCII codes to characters

Question

I have a string containing hex code values of ASCII characters, e.g. "666f6f626172". I want to convert it to the corresponding string ("foobar").

This is working but ugly:

"666f6f626172".scan(/../).map(&:hex).map(&:chr).join # => "foobar"

Is there a better (more concise) way? Could unpack be helpful somehow?

@Stefan. Yes, like that. Could you please post this as an answer? — undur_gongor, Apr 09 '14 at 09:23

score 64 · Accepted Answer · answered Apr 09 '14 at 10:07

64

You can use Array#pack:

["666f6f626172"].pack('H*')
#=> "foobar"

H is the directive for a hex string (high nibble first).

answered Apr 09 '14 at 10:07

Stefan

33

`pack`/`unpack` will remain a mystery to me forever. – undur_gongor Apr 09 '14 at 10:13

score 23 · Answer 2 · answered Apr 09 '14 at 17:19

23

Stefan has nailed it, but here's an alternative you may want to tuck away for another time and place:

"666f6f626172".gsub(/../) { |pair| pair.hex.chr } # => "foobar"

answered Apr 09 '14 at 17:19

Cary Swoveland

2 Answers2