# Constructing a string from hex value **URL:** \ **Category:** Ruby\ **Created:** [September 6, 2006, 4:06pm UTC](https://www.ruby-forum.com/t/constructing-a-string-from-hex-value/67750 "2006-09-06T16:06:07Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Srdjan\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dec6dc/32.png) [@Srdjan\_M](https://www.ruby-forum.com/u/Srdjan_M)\ **Post date:** [September 6, 2006, 4:06pm UTC](https://www.ruby-forum.com/t/constructing-a-string-from-hex-value/67750/1 "2006-09-06T16:06:07Z")
hi, How do I construct a string out of hex values? In other words I want to give exact hex value for each byte in the string. So I would have soemthing like 0x2a, 0x7e, 0x0a, 0x7e If I go through Fixnum I get my string to contain numbers 48, 115, 10, 115 but I do not want that but rather a string of ASCII(48), ACII(115),… Thanks srdjan ---
**Author:** ![Srdjan\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dec6dc/32.png) [@Srdjan\_M](https://www.ruby-forum.com/u/Srdjan_M)\ **Post date:** [September 6, 2006, 4:30pm UTC](https://www.ruby-forum.com/t/constructing-a-string-from-hex-value/67750/2 "2006-09-06T16:30:08Z")
Srdjan M. wrote: > hi, > > How do I construct a string out of hex values? > In other words I want to give exact hex value for each byte in the > string. So I would have soemthing like > > 0x2a, 0x7e, 0x0a, 0x7e > > If I go through Fixnum I get my string to contain numbers 48, 115, 10, > 115 but I do not want that but rather a string of ASCII(48), > ACII(115),… > > Thanks > > srdjan irb(main):001:0\> p = “\x2a\x7e\x0a\x7e” =\> “\*~\n~” irb(main):002:0\> ---
**Author:** ![Srdjan\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dec6dc/32.png) [@Srdjan\_M](https://www.ruby-forum.com/u/Srdjan_M)\ **Post date:** [September 6, 2006, 4:32pm UTC](https://www.ruby-forum.com/t/constructing-a-string-from-hex-value/67750/3 "2006-09-06T16:32:12Z")
Srdjan M. wrote: > 0x2a, 0x7e, 0x0a, 0x7e [0x2a, 0x7e, 0x0a, 0x7e].pack ‘C\*’ ---
**Author:** ![Srdjan\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dec6dc/32.png) [@Srdjan\_M](https://www.ruby-forum.com/u/Srdjan_M)\ **Post date:** [September 6, 2006, 4:44pm UTC](https://www.ruby-forum.com/t/constructing-a-string-from-hex-value/67750/4 "2006-09-06T16:44:14Z")
“Srdjan M.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes: > How do I construct a string out of hex values? > In other words I want to give exact hex value for each byte in the > string. So I would have soemthing like > > 0x2a, 0x7e, 0x0a, 0x7e > > If I go through Fixnum I get my string to contain numbers 48, 115, 10, > 115 but I do not want that but rather a string of ASCII(48), > ACII(115),… irb(main):001:0\> a = [0x2a, 0x7e, 0x0a, 0x7e] =\> [42, 126, 10, 126] irb(main):002:0\> a.map{|x|x.chr}.join =\> “\*~\n~” If all you have is the string representation of the hex values (say, if you’re reading hex values from a file), you have to do just a tiny bit more to first convert the hex values into integers: irb(main):001:0\> a = %w[2a 7e 0a 7e] =\> [“2a”, “7e”, “0a”, “7e”] irb(main):002:0\> a.map{|x|x.hex.chr}.join =\> “\*~\n~” But only just barely more. ---
**Author:** ![Srdjan\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dec6dc/32.png) [@Srdjan\_M](https://www.ruby-forum.com/u/Srdjan_M)\ **Post date:** [September 6, 2006, 5:08pm UTC](https://www.ruby-forum.com/t/constructing-a-string-from-hex-value/67750/5 "2006-09-06T17:08:16Z")
thanks a lot for you help ---
**Author:** ![Srdjan\_M](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/dec6dc/32.png) [@Srdjan\_M](https://www.ruby-forum.com/u/Srdjan_M)\ **Post date:** [September 6, 2006, 5:20pm UTC](https://www.ruby-forum.com/t/constructing-a-string-from-hex-value/67750/6 "2006-09-06T17:20:18Z")
On Wed, 6 Sep 2006, Srdjan M. wrote: > ACII(115),… > > Thanks > > srdjan the append operator of String does what you want with Fixnums. as others have pointed out you can use pack to initially contruct it. but you can also continue to build it up with a simple ‘\<\<’ harp:~ \> cat a.rb s = [0x2a, 0x7e, 0x0a, 0x7e].inject(’’){|s,c| s \<\< c} p s[0] p 0x2a harp:~ \> ruby a.rb 42 42 regards. -a