complex() raises ValueError when parsing a string argument containing both real and imaginary where one of the real or imaginary is a decimal.

To reproduce:

>>> complex("1.1 + 2.1j")
ValueError: complex() arg is a malformed string

>>> complex("2.1j")
2.1j

>>> complex("1.1 + 2j")
ValueError: complex() arg is a malformed string

>>> complex("1 + 2.1j")
ValueError: complex() arg is a malformed string 

Expected results:

>>> complex("1.1 + 2.1j")
(1.1 + 2.1j)

>>> complex("2.1j")
2.1j

>>> complex("1.1 + 2j")
(1.1 + 2j)

>>> complex("1 + 2.1j")
(1 + 2.1j)

This affects all versions up to Python 3.1.2. I haven't tested any of the development builds.

Tests were conducted on a Windows XP 32 bit machine.