STINNER Victor added the comment:
You should use complex(a, b) to have a reliable behaviour.
Python parse doesn't see "-1-0j" as a complex literal, but as (-1)-(0j):
int-complex. Example with the AST output:
>>> ast.dump(ast.parse('-1-0j'))
'Module(body=[Expr(value=BinOp(left=UnaryOp(op=USub(), operand=Num(n=1)),
op=Sub(), right=Num(n=0j)))])'
It looks like complex has the same behaviour than float:
>>> x=-0.0; x=0+x; x.real
0.0
>>> x=-0.0; x=0-x; x.real
0.0
>>> x=complex(0.0, -0.0); x=0+x; (x.real, x.imag)
(0.0, 0.0)
>>> x=complex(0.0, -0.0); x=0-x; (x.real, x.imag)
(0.0, 0.0)
zero sign is lost on int+complex, int-complex, int+complex, int-complex.
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nosy: +haypo, mark.dickinson
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Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue25839>
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