#範例2-3：使用numpy+matplotlib, 繪圖sin(x),cos(x)
import numpy as np
import matplotlib.pyplot as plt

#一個圖：sin(x)
#numpy的pi = np.pi
x = np.arange(0,np.pi*8,0.01)
#numpy 的sin = np.sin
y = np.sin(x)
plt.plot(x,y,color='red')
plt.show()


#二個圖：sin(x), cos(x)
x = np.arange(-np.pi*4,np.pi*4,0.01)
y1 = np.sin(x)
y2 = np.cos(x)
plt.plot(x,y1,color='red',label='y=sinx')
plt.plot(x,y2,color='blue',label='y=cosx')
plt.title = 'sin(x) and cos(x)'
plt.xlabel('angel(pi)')
plt.ylabel('amplitude',rotation=0)
#圖例標籤
plt.legend()
#plt.legend(['y=sinx','y=cosx'])
plt.show()

#三個圖：sin(x), cos(x), sin(x)+cos(x)
x = np.arange(-np.pi*4,np.pi*4,0.01)
y1 = np.sin(x)
y2 = np.cos(x)
y3 = y1 + y2
plt.plot(x,y1,color='red',label='y=sinx')
plt.plot(x,y2,color='blue',label='y=cosx')
plt.plot(x,y3,color='green',label='y=sinx+cosx')
plt.title = 'sin(x) and cos(x)'
#設定xlabe，ylabell的位置：position=
plt.xlabel('angel(pi)',position=(0.95,0))
plt.ylabel('amplitude',position=(0,1),rotation=0)

#圖例標籤的位置 loc = "lower left"
'''
'best'	0
'upper right'	1
'upper left'	2
'lower left'	3
'lower right'	4
'right'	5
'center left'	6
'center right'	7
'lower center'	8
'upper center'	9
'center'	10 
'''
plt.legend(loc="lower left")
#plt.legend(['y=sinx','y=cosx'])

#設定：不顯示圖片的四邊黑框線
ax = plt.gca()
ax.spines["top"].set_color("none") 
ax.spines["right"].set_color("none")
ax.spines["bottom"].set_position(("data", 0)) 
ax.spines["left"].set_position(("data", 0))


plt.show()