隨機numbers-只有長度爲1的陣列可以被轉換到Python標量

Question

from math import sin, cos, pi 
import numpy as np 
N=10 

a=np.random.randint(0, 360+1, N) 
print (a) 

theta=a*pi/180 
print(theta) 

x=[cos(theta)] 
print(x) 
y=[sin(theta)] 
print(y) 

---

TypeError         Traceback (most recent call last) 
<ipython-input-47-632b45c2aba1> in <module>() 
     9 theta=a*pi/180 
    10 print(theta) 
---> 11 x=[cos(theta)] 
    12 print(x) 
    13 y=[sin(theta)] 

TypeError: only length-1 arrays can be converted to Python scalars 

Answer 1

使用np.cos(theta)代替cos(theta)嘗試。 sin也是如此。

只有NumPy函數可以應用於標量和數組。常規cos()和sin()而不是隻期望標量參數，失敗的例子中，當你試圖應用這些尺寸的NumPy的陣列上10

NumPy的cos文檔：http://docs.scipy.org/doc/numpy/reference/generated/numpy.cos.html cos文檔：https://docs.python.org/2/library/math.html