def y(x):
if x <0:
return np.cos(x)
else:
np.exp(-x)
x = np.arange(-2*np.pi,2*np.pi,0.1)
plt.plot(x,y(x))
plt.show()
This function supposed to plot y (x) as cos (x) if the x value is less than zero, otherwise exp (-x).
I wrote the code, but it gave me an error. How I can fix the error?
I get this error
ValueError: The truth value of an array with more than one element is ambiguous.
Use a.any() or a.all()
There are better ways to do this if performance is an issue, but one solution is to serialize your function to apply it to the whole array
def y(x):
if x <0:
return np.cos(x)
else:
return np.exp(-x)
vfunc = np.vectorize(y)
x = np.arange(-2*np.pi,2*np.pi,0.1)
plt.plot(x,vfunc(x))
plt.show()
Probably better in terms of performance:
def y(x):
return np.concatenate((np.cos(x[x<0]), np.exp(-x[x>=0])))
x = np.arange(-2*np.pi,2*np.pi,0.1)
plt.plot(x,y(x))
plt.show()
