Forum: Ruby XOR two binary strings

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Gary C. (Guest)
on 2009-01-12 21:28
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
Jan-Erik R. (Guest)
on 2009-01-12 21:39
(Received via mailing list)
Gary C. 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)
on 2009-01-12 21:54
(Received via mailing list)
Gary C. 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
Robert K. (Guest)
on 2009-01-13 09:25
(Received via mailing list)
On 12.01.2009 20:52, Joel VanderWerf wrote:
> 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
Brian C. (Guest)
on 2009-01-13 11:21
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"
Sandor Szücs (Guest)
on 2009-01-20 19:47
(Received via mailing list)
On 12.01.2009, at 20:27, Gary C. 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"  # => "\000\001\001\000"


Hth. regards, Sandor
Szücs
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