Mark Dickinson added the comment: This is something that comes up repeatedly on the bug tracker. There's no bug here in the complex type or the repr. What there *is* is a limitation resulting from the fact that Python doesn't have *imaginary* literals, only *complex* literals. So in:
-1-0j the 0j is already a complex number with both real and imaginary parts equal to 0.0. Then -1 gets promoted to a complex number with real part -1 and imaginary part 0.0. And now you're doing: complex(-1.0, 0.0) - complex(0.0, 0.0) which naturally gives an imaginary part of +0.0 rather than 0.0. You'll see the same issue in C: there was an attempt to fix it in C99 by introducing Imaginary types, but those Imaginary types haven't been widely adopted. The most recent reincarnation of the C standard finally introduces a macro that lets you instantiate a complex number in terms of its real and imaginary components (instead of doing real_part + imag_part * I); this is something that Python already has in the form of the complex constructor. Closing as not a bug. ---------- resolution: -> not a bug status: open -> closed _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue25839> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
