如何圍捕複雜無（1.9999999999999998-2j）如（2-2j）在python

Question

當我試圖使用

print(round(x,2)) 

它顯示

Traceback (most recent call last): 
    File "C:\Python34\FFT.py", line 22, in <module> 
    print(round(x,2)) 
TypeError: type complex doesn't define __round__ method 

Answer 1

圓形實部和虛部單獨並結合他們：

>>> num = 1.9999999999999998-2j 
>>> round(num.real, 2) + round(num.imag, 2) * 1j 
(2-2j) 

Answer 2

如果你想要做的是代表四捨五入值示，而不是修改本身的價值，下面的工作：

>>> x=1.9999999999999998-2j 
>>> print("{:g}".format(x)) 
2-2j 

參見：Format Specification Mini-Language。