Forum: Ruby Character encoding in 1.9

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D1293dba7ab354e671044619fc1a00d7?d=identicon&s=25 Andrew S. (andrew_s)
on 2012-12-24 21:34
I have some code in 1.8 that would strip certain special characters out
of a string (escape sequences in Telnet specifically, such as
\377\373\001).

I've moved to 1.9 and now that code fails with "invalid multibyte
escape".

I've looked at some of the tutorials regarding encodings in 1.9 and to
be honest I find them very intimidating.  I'm hoping someone can suggest
a quick fix?

Here's the code:

[3,4,5,6,7].each do |n|
    line.gsub!(/#{('\377\37' + n.to_s + '\001')}/,"")
end

Many thanks in advance!

 - Andrew
A226fe2449820fed93c25c6cbf3ca6e5?d=identicon&s=25 Nathan Beyer (Guest)
on 2012-12-25 05:29
(Received via mailing list)
Check out the Regexp documentation, specifically the 'new'/'compile'
method: http://www.ruby-doc.org/core-1.9.3/Regexp.html#method-c-new. I
think you'll need to use Regexp.compile to create an "encoding-less"
regular expression.

I would guess something like this -

[3,4,5,6,7].each do |n|
    line.gsub!(Regexp.compile('\377\37' + n.to_s + '\001', nil, 'n'),"")
end

You'll have to fiddle with it, as I didn't have a chance to test it out
to
see if this actually works. I'd have to know the encoding the 'line'
variable to accurately test it anyway.
54404bcac0f45bf1c8e8b827cd9bb709?d=identicon&s=25 7stud -- (7stud)
on 2012-12-25 09:15
line = "hello\377\373\001 \377\374\001 \377\375\001world"

(3..7).each do |n|
  pattern = "\377" << (0370 + n).chr << "\001"
  line.gsub! pattern, " "
  p line
end

--output:--
"hello  \377\374\001 \377\375\001world"
"hello    \377\375\001world"
"hello     world"
"hello     world"
"hello     world"
54404bcac0f45bf1c8e8b827cd9bb709?d=identicon&s=25 7stud -- (7stud)
on 2012-12-25 10:09
line = "hello\377\373\001 \377\374\001 \377\375\001world"
p line

regex = /\377[\373-\377]\001/

line.gsub! regex, ''
p line

--output:--
"hello\xFF\xFB\x01 \xFF\xFC\x01 \xFF\xFD\x01world"
"hello  world"
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