On 2/21/07, Dick Moores <[EMAIL PROTECTED]> wrote: > But there's syntax(?) there I've never seen before. "['','-'][n<0]". > I see it works: > > >>> n = -6 > >>> ['','-'][n<0] > '-' > >>> n = 98 > >>> ['','-'][n<0] > '' > > What's this called? I'd like to look it up.
['', '-'] is a list with two elements: an empty string, and the string '-'. [n<0] is an index into the list. For example: >>> a = ['First Element', 'Second Element'] >>> a[False] 'First Element' >>> a[True] 'Second Element' This works because int(True) is 1 and int(False) is 0. Personally, I find using boolean values to index a list to be hard to read. If I ever came back to looking at the code again, I'd rather have written something like this: sign = '' if (n < 0): sign = '-' It's an extra line of code, but it's a lot less cryptic to me. -- Jerry _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
