operator precedence with complex numbers

Question

This should be self-explanatory

>>> (1+2j).real  #Normal Usage
1.0
>>> (1+2j).imag  #Normal Usage
2.0
>>> 1+2j.real  #Normal Usage
1.0
>>> 1+2j.imag  #Flips Out
3.0
>>> 123+657j.real
123.0
>>> 123+657j.imag
780.0

z.imag somehow adds up the real and imaginary parts.
I found this interesting .. is this a bug or is this an intentional feature?

Answer 1

The problem is that 1+2j.imag is being parsed as 1+(2j.imag) . Clearly 2j.imag is 2.0 , so 1+2j returns 3.0 . When you do 1+2j.real , Python adds 1 and 2j.real . 2j.real is 0.0 , so you get the correct answer 1.0 in return.

If you parenthesize the complex number, like in your first two examples, you will get the expected results.

Answer 2

This is an operator precedence issue. . has higher precedence than + , so you are effectively doing

1+(2j.imag)

which of course is 3.

It is a Very Good Idea™ to always parenthesize complex number literals.

Answer 3

No madness there, really. Here's what happens: the '.' operator has precedence over the +, that's all. That means

>>> 1+2j.imag

is evaluated as 1 + (2j.imag) which is 1 + 2 which is 3. The same is valid for the other examples.