python的sympy怎样判断是不是复数？

Question

import sympy
x=sympy.symbols('x')
s='x**6 + x**5 + x**4 + x**3 + x**2 + x + 1'.replace(" ","")
r=sympy.solve(s,x)print(r)for i in r:    print(i)

结果是： 
-cos(pi/7) - Isin(pi/7), -cos(pi/7) + Isin(pi/7), cos(2pi/7) - Isin(2pi/7), cos(2pi/7) + Isin(2pi/7), -cos(3pi/7) - Isin(3pi/7), -cos(3pi/7) + Isin(3pi/7)]
-cos(pi/7) - I*sin(pi/7)
-cos(pi/7) + I*sin(pi/7)
cos(2pi/7) - Isin(2*pi/7)
cos(2pi/7) + Isin(2*pi/7)
-cos(3pi/7) - Isin(3*pi/7)
-cos(3pi/7) + Isin(3*pi/7)
我该怎样判断-cos(3pi/7) + Isin(3*pi/7)是不是一个复数呢？

Answer 1

直接用isinstance进行x = 2j+1if isinstance(x, complex):    print('X is complex')如果是numpy直接有方法 numpy.iscomplex(x)