Ruby String ASCII operation?

Question

Is it possible to do some ASCII options in Ruby, like what we did in Cpp?

char *s = "test string";
for(int i = 0 ; i < strlen(s) ; i++) printf("%c",s[i]);
// expected output: vguv"uvtkpi

How do I achieve a similar goal in Ruby? From some research I think String.each_byte might help here, but I'm thinking to use high order programming (something like Array.map) to translate the string directly, without using an explicit for loop.

The task I'm trying to solve: Referring to this page, I'm trying to solve it using Ruby, and it seems a character-by-character translation is needed to apply to the string.

Why? We very seldom need to operate at that level in Ruby, so it sounds like you're trying to accomplish something in a very C++ way that we'd do entirely differently in Ruby. Explain what data you're working with, and why, and we can probably show you the Ruby way to do it, not show you the C++ way to do it in Ruby. — the Tin Man
– the Tin Man, Commented Jan 5, 2014 at 3:41
@theTinMan Tin Man Thanks for asking about the purpose. I updated my question. — songyy
– songyy, Commented Jan 5, 2014 at 3:47

the Tin Man · Accepted Answer · 2014-01-05 08:53:14Z

4

Pay close attention to the hint given by the question in the Challenge, then use String's tr method:

"test string".tr('a-z', 'c-zab')
# => "vguv uvtkpi"

An additional hint to solve the problem is, you should only be processing characters. Punctuation and spaces should be left alone.

Use the above tr on the string in the Python Challenge, and you'll see what I mean.

edited Jan 5, 2014 at 8:53

answered Jan 5, 2014 at 4:43

the Tin Man

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2 Comments

Cary Swoveland Over a year ago

Nice solution, Sn, even if you wanted to convert the space: tr('a-z ', 'c-zab\"')

the Tin Man Over a year ago

It's not necessary to escape the double-quote when it's enclosed in single quotes: ' '.tr(' ', '"') # => "\"".

falsetru · Accepted Answer · 2014-01-05 12:03:34Z

1

Use String#each_char and String#ord and Integer#chr:

s = "test string"
s.each_char.map { |ch| (ch.ord + 2).chr }.join
# => "vguv\"uvtkpi"

or String#each_byte:

s.each_byte.map { |b| (b + 2).chr }.join
# => "vguv\"uvtkpi"

or String#next:

s.each_char.map { |ch| ch.next.next }.join
# => "vguv\"uvtkpi"

edited Jan 5, 2014 at 12:03

answered Jan 5, 2014 at 3:42

falsetru

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Comments

daremkd · Accepted Answer · 2014-01-05 03:50:18Z

0

You can use codepoints or each_codepoint methods, for example:

old_string = 'test something'
new_string = ''

old_string.each_codepoint {|x| new_string << (x+2).chr}

p new_string #=> "vguv\"uqogvjkpi"

answered Jan 5, 2014 at 3:50

daremkd

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