What's the Opposite of Chr() in Ruby

What's the opposite of chr() in Ruby?

If String#ord didn't exist in 1.9, it does in 2.0:

"A".ord #=> 65

Trying to understand the Ruby .chr and .ord methods

According to Integer#chr you can use the following to force the encoding to be UTF_8.

22909.chr(Encoding::UTF_8)
#=> "好"

To list all available encoding names

Encoding.name_list
#=> ["ASCII-8BIT", "UTF-8", "US-ASCII", "UTF-16BE", "UTF-16LE", "UTF-32BE", "UTF-32LE", "UTF-16", "UTF-32", ...]

A hacky way to get the maximum number of characters

2000000.times.reduce(0) do |x, i|
  begin
    i.chr(Encoding::UTF_8)
    x += 1
  rescue
  end

  x
end
#=> 1112064

How to use .ord and .chr properly in a loop?

You want a mapping like this:

input:  abcdefghijklmnopqrstuvwxyz
output: wxyzabcdefghijklmnopqrstuv

Unfortunately your approach doesn't work for the first 4 letters:

("a".ord - 4).chr #=> "]"
("b".ord - 4).chr #=> "^"
("c".ord - 4).chr #=> "_"
("d".ord - 4).chr #=> "`"

I'd use String#tr. It replaces each occurrence in the first string with the corresponding character in the second string:

"m^aerx%e&gsoi!".tr("abcdefghijklmnopqrstuvwxyz", "wxyzabcdefghijklmnopqrstuv")
#=> "i^want%a&coke!"

There's also a "c1-c2 notation to denote ranges of characters":

"m^aerx%e&gsoi!".tr("a-z", "w-za-v")
#=> "i^want%a&coke!"

The documentation further says:

If to_str is shorter than from_str, it is padded with its last character in order to maintain the correspondence.

So it can be used to easily replace the "special characters" with a space:

"m^aerx%e&gsoi!".tr("a-z@#$%^&*", "w-za-v ")
#=> "i want a coke!"

gsub non ASCII character in Ruby

>> string="foo\xC2bar"
=> "foo\xC2bar"
>> string.force_encoding"ASCII-8BIT"
=> "foo\xC2bar"
>> string.gsub(194.chr, '')
=> "foobar"

English words (ONE, TWO, THREE) to number(1,2,3) in ruby

I created a hash up-to twenty for all words and only for tens(thirty, forty, fifty etc.). Using Reg-ex took off two words and added them for example twenty two is addition of 20+2=22; right now my script only works till hundred, but it can be extended for numbers over 100 and so on.

How to identify character's language in Ruby/Rails?

The UNICODE standard is divided into "blocks". Go here:

http://www.unicode.org/charts/

http://en.wikipedia.org/wiki/Unicode_block

http://www.unicode.org/versions/Unicode6.0.0/

and find unicode blocks (intervals) for each language.

My guess:

• English
• Hebrew
• Russian

So for you its the matter of simple number comparsion for each character (unicode ordinal value). Very simple.

Integer value of a character in ruby?

You probably want String#ord:

% irb
ruby-1.9.2-head > 'a'.ord
 => 97 

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