Velocity Reviews > Ruby > XOR two binary strings

# XOR two binary strings

Gary Chris
Guest
Posts: n/a

 01-12-2009
Howdy,

I am having difficulty finding how to XOR 2 binary strings.
Is there a builtin function for this ?
Something like
return string_one ^ string_two

Thanks
--
Posted via http://www.ruby-forum.com/.

Jan-Erik R.
Guest
Posts: n/a

 01-12-2009
Gary Chris schrieb:
> Howdy,
>
> I am having difficulty finding how to XOR 2 binary strings.
> Is there a builtin function for this ?
> Something like
> return string_one ^ string_two
>
> Thanks

what do you mean by binary Strings?
"011101"?
use
Integer("0b#{binarystring}")
to convert it to an integer, then use the XOR and later use
String#to_s(2)
to convert it back again.

Joel VanderWerf
Guest
Posts: n/a

 01-12-2009
Gary Chris wrote:
> Howdy,
>
> I am having difficulty finding how to XOR 2 binary strings.
> Is there a builtin function for this ?
> Something like
> return string_one ^ string_two
>
> Thanks

All I can think of at the moment:

a = [0b00000001, 0b00001000].pack("C*")
b = [0b10000001, 0b01000000].pack("C*")

c = a.unpack("C*").zip(b.unpack("C*"))
c = c.map {|x,y| x^y}
c = c.pack("C*")
p c

--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407

Robert Klemme
Guest
Posts: n/a

 01-13-2009
On 12.01.2009 20:52, Joel VanderWerf wrote:
> Gary Chris wrote:
>> Howdy,
>>
>> I am having difficulty finding how to XOR 2 binary strings.
>> Is there a builtin function for this ?
>> Something like
>> return string_one ^ string_two
>>
>> Thanks

>
> All I can think of at the moment:
>
> a = [0b00000001, 0b00001000].pack("C*")
> b = [0b10000001, 0b01000000].pack("C*")
>
> c = a.unpack("C*").zip(b.unpack("C*"))
> c = c.map {|x,y| x^y}
> c = c.pack("C*")
> p c

There's also

irb(main):002:0> ("00000001".to_i(2) ^ "0110".to_i(2)).to_s(2)
=> "111"

Kind regards

robert

--
remember.guy do |as, often| as.you_can - without end

Brian Candler
Guest
Posts: n/a

 01-13-2009
I'm not sure if "binary string" meant a string of the form "000101...",
or if it meant two strings treated as arrays of bytes.

If the latter, then

irb(main):001:0> require 'enumerator'
=> true
irb(main):002:0> s1 = "abc".to_enum(:each_byte)
=> #<Enumerable::Enumerator:0xb7cc85dc>
irb(main):003:0> s2 = "\x02\x04\x06".to_enum(:each_byte)
=> #<Enumerable::Enumerator:0xb7cc02c4>
irb(main):004:0> s1.zip(s2).map{ |x,y| (x^y).chr }.join
=> "cfe"

ruby 1.9 lets you shorten this to

irb(main):001:0> "abc".bytes.zip("\x02\x04\x06".bytes).map { |x,y|
(x^y).chr }.join
=> "cfe"
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Sandor Szücs
Guest
Posts: n/a

 01-20-2009

On 12.01.2009, at 20:27, Gary Chris wrote:

> am having difficulty finding how to XOR 2 binary strings.
> Is there a builtin function for this ?
> Something like
> return string_one ^ string_two

There is also facets:

irb> require 'facets/string/xor'
irb> "\000\000\001\001" ^ "\000\001\000\001" # =3D> "\000\001\001\000"

Hth. regards, Sandor Sz=FCcs
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