On Mon, Jan 6, 2014 at 3:49 PM, Roy Smith <r...@panix.com> wrote: > Thanks. But, I see I didn't formulate my problem statement well. I was > (naively) assuming there wouldn't be a built-in codec for rot-13. Let's > assume there isn't; I was trying to find a case where you had to treat > the data as integers in one place and text in another. How would you do > that?
I assumed that you would have checked that one, and answered accordingly :) Though I did dig into the EBCDIC part of the question. My thinking is that, if you're working with integers, you probably mean either bytes (so encode it before you do stuff - typical for crypto) or codepoints / Unicode ordinals (so use ord()/chr()). In other languages there are ways to treat strings as though they were arrays of integers (lots of C-derived languages treat 'a' as 97 and "a"[0] as 97 also; some extend this to the full Unicode range), and even there, I almost never actually use that identity much. There's only one case that I can think of where I did a lot of string<->integer-array transmutation, and that was using a diff function that expected an integer array - if the transformation to and from strings hadn't been really easy, that function would probably have been written to take strings. The Py2 str.translate() method was a little clunky to use, but presumably fast to execute - you build up a lookup table and translate through that. The Py3 equivalent takes a dict mapping the from and to values. Pretty easy to use. And it lets you work with codepoints or strings, as you please. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
