While this thread was amusing to read, *changing* Python from the engineering notation to mathematical notation for imaginary numbers is not going to happen. 'i' has ambiguity problems relative to '1' and 'l' in too many fonts - 'j', on the other hand, almost always uses a visually distinct glyph. And whether 'i' or 'j' seems more natural to you will depend on whether or not you have an electrical engineering background (as noted earlier in the thread, 'i' refers to current in electrical engineering).

If you care about the precise formatting of a complex number, write your own formatting function rather than relying on the exact format produced by "repr(num)".

Having an alternate constructor for complex objects that was more forgiving about 'i' vs 'j' also doesn't offer a huge benefit over the simple "x = complex(arg.replace('i', 'j')".

So while I have some sympathy for mathematicians that are frustrated by having to train their fingers to hit 'j' instead of 'i', that's not a good enough reason to change the language syntax or the behaviour of the complex() builtin. (See also http://www.boredomandlaziness.org/2011/02/status-quo-wins-stalemate.html)