将双引号更改为单引号

Question

I'm working on a project in Ruby. The library I'm using returns a string in double quotes, for example: "\\x00\\x40" . Since the string is in double quotes, any hex that can be converted to an ASCII character is converted. Therefore, when I print, I actually see: "\\x00@" .

I figured out that, if I use single quotes, then the string will print in pure hex (without conversion), which is what I want. How do I change a double quoted string to single quoted?

I do not have any way to change the return type in the library since it is a C extension, and I can't figure out where the value is being returned from. Any ideas greatly appreciated.

Answer 1

"\\x00\\x40" and '\\x00\\x40' produce totally different strings.

"\\x00\\x40" creates a 2 byte string with hex values 0x00 and 0x40 :

"\x00\x40".length
# => 2

"\x00\x40".chars.to_a
# => ["\u0000", "@"]

'\\x00\\x40' creates a string with 8 characters:

'\x00\x40'.length
# => 8

'\x00\x40'.chars.to_a
# => ["\\", "x", "0", "0", "\\", "x", "4", "0"]

This is done by Ruby's parser and you cannot change it once the string is created.

However, you can convert the string to get its hexadecimal representation.

String#unpack decodes the string as a hex string, ie it returns the hex value of each byte as a string:

hex = "\x00\x40".unpack("H*")[0]
# => "0040"

String#gsub adds/inserts \\x every 2 bytes:

hex.gsub(/../) { |s| '\x' + s }
# => "\\x00\\x40"