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

Question

In many languages there\'s a pair of functions, chr() and ord(), which convert between numbers and character values. In some languages, ord()

Answer 1

I'd like to +1 dylanfm and AShelly's comment but add the [0]:

'A'.unpack('C')[0]

The unpack call returns an Array containing a single integer, which is not always accepted where an integer is wanted:

$ ruby -e 'printf("0x%02X\n", "A".unpack("C"))'
-e:1:in `printf': can't convert Array into Integer (TypeError)
    from -e:1
$ ruby -e 'printf("0x%02X\n", "A".unpack("C")[0])'
0x41
$ 

I'm trying to write code that works on Ruby 1.8.1, 1.8.7 and 1.9.2.

Edited to pass C to unpack in uppercase, because unpack("c") gives me -1 where ord() gives me 255 (despite running on a platform where C's char is signed).

Answer 2

Additionally, if you have the char in a string and you want to decode it without a loop:

puts 'Az'[0]
=> 65
puts 'Az'[1]
=> 122

Answer 3

How about

puts ?A

Answer 4

In Ruby up to and including the 1.8 series, the following will both produce 65 (for ASCII):

puts ?A
'A'[0]

The behavior has changed in Ruby 1.9, both of the above will produce "A" instead. The correct way to do this in Ruby 1.9 is:

'A'[0].ord

Unfortunately, the ord method doesn't exist in Ruby 1.8.

Answer 5

You can have these:

65.chr.ord
'a'.ord.chr

Answer 6

If you don't mind pulling the values out of an array, you can use "A".bytes