Python numpy.cos()用法及代码示例

numpy.cos(x [，out])= ufunc'cos')：此数学函数可帮助用户计算所有x(作为数组元素)的三角余弦。

参数：

array  : [array_like]elements are in radians. 

2pi Radians = 360 degrees

返回：

An array with trignometric cosine 
of x for all x i.e. array elements 

代码1：工作

# Python program explaining 
# cos() function 
  
import numpy as np 
import math 
  
in_array = [0, math.pi / 2, np.pi / 3, np.pi] 
print ("Input array : \n", in_array) 
  
cos_Values = np.cos(in_array) 
print ("\nCosine values : \n", cos_Values)

输出：

Input array : 
 [0, 1.5707963267948966, 1.0471975511965976, 3.141592653589793]

Cosine values : 
 [  1.00000000e+00   6.12323400e-17   5.00000000e-01  -1.00000000e+00]

代码2：图形表示

# Python program showing 
# Graphical representation of  
# cos() function 
  
import numpy as np 
import matplotlib.pyplot as plt 
  
in_array = np.linspace(-(2*np.pi), 2*np.pi, 20) 
out_array = np.cos(in_array) 
  
print("in_array : ", in_array) 
print("\nout_array : ", out_array) 
  
# red for numpy.cos() 
plt.plot(in_array, out_array, color = 'red', marker = "o") 
plt.title("numpy.cos()") 
plt.xlabel("X") 
plt.ylabel("Y") 
plt.show()

输出：

in_array :  [-6.28318531 -5.62179738 -4.96040945 -4.29902153 -3.6376336  -2.97624567
 -2.31485774 -1.65346982 -0.99208189 -0.33069396  0.33069396  0.99208189
  1.65346982  2.31485774  2.97624567  3.6376336   4.29902153  4.96040945
  5.62179738  6.28318531]

out_array :  [ 1.          0.78914051  0.24548549 -0.40169542 -0.87947375 -0.9863613
 -0.67728157 -0.08257935  0.54694816  0.94581724  0.94581724  0.54694816
 -0.08257935 -0.67728157 -0.9863613  -0.87947375 -0.40169542  0.24548549
  0.78914051  1.        ]

参考文献：
https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.cos.html#numpy.cos
。