Getting an ASCII character code in Ruby using `?` (question mark) fails

ruby char ascii
dorr picture dorr · Aug 13, 2009 · Viewed 56.2k times · Source

I'm in a situation where I need the ASCII value of a character (for Project Euler question #22, if you want to get specific) and I'm running into an issue.

Being new to ruby, I googled it, and found that ? was the way to go: ?A or whatever. But when I incorporate it into my code, the result of that statement is the string "A"—no character code. Same issue with [0] and slice(0), both of which should theoretically return the ASCII code.

The only thing I can think of is that this is a ruby version issue. I'm using 1.9.1-p0, having upgraded from 1.8.6 this afternoon. I cheated a little going from a working version of Ruby, in the same directory, I figured I probably already had the files that don't come bundled with the .zip file, so I didn't download them.

So why exactly are all my ASCII codes being turned into actual characters?

Answer

Chuck picture Chuck · Aug 13, 2009

Ruby before 1.9 treated characters somewhat inconsistently. ?a and "a"[0] would return an integer representing the character's ASCII value (which was usually not the behavior people were looking for), but in practical use characters would normally be represented by a one-character string. In Ruby 1.9, characters are never mysteriously turned into integers. If you want to get a character's ASCII value, you can use the ord method, like ?a.ord (which returns 97).

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