实现自己既定的目标,必须能耐得住寂寞单干。
用途:实现矩阵的e的次幂操作
代码示例:
import numpy as np v = [1,2,3] print(np.exp(v))运行结果:
[ 2.71828183 7.3890561 20.08553692]
用途:实现矩阵的次方操作
代码示例:
import numpy as np v = [1,2,3] print(np.sqrt(v))运行结果:
[1. 1.41421356 1.73205081]
用途:将矩阵拉伸成一个向量
代码示例:
import numpy as np m = np.array([[1,2],[3,4]]) v = m.ravel() print(v)运行结果:
[1 2 3 4]
矩阵的转置
代码示例:
import numpy as np m = np.array([[1,2],[3,4],[5,6]]) print(m.T)运行结果:
[[1 3 5] [2 4 6]]
函数:hstack()
代码示例:
import numpy as np a = np.array([[1,2,3],[1,2,3]]) b = np.array([[4,5,6],[4,5,6]]) print(np.hstack((a,b)))运行结果:
[[1 2 3 4 5 6] [1 2 3 4 5 6]]
纵向拼接函数:vstack()
代码示例:
import numpy as np a = np.array([[1,2,3],[1,2,3]]) b = np.array([[4,5,6],[4,5,6]]) print(np.vstack((a,b)))运行结果:
[[1 2 3] [1 2 3] [4 5 6] [4 5 6]]
函数:hsplit()
方式一:按拆分次数平均拆分
代码示例:
import numpy as np m = np.array([[1,2,3,4,5,6,7,8,9],[1,2,3,4,5,6,7,8,9]]) print(np.hsplit(m,3))运行结果:
[array([[1, 2, 3], [1, 2, 3]]), array([[4, 5, 6], [4, 5, 6]]), array([[7, 8, 9], [7, 8, 9]])]
方式二:给出拆分点进行拆分(拆分点以元组的方式给出)
代码示例:
import numpy as np m = np.array([[1,2,3,4,5,6,7,8,9],[1,2,3,4,5,6,7,8,9]]) print(np.hsplit(m,(4,5)))运行结果:
[array([[1, 2, 3, 4], [1, 2, 3, 4]]), array([[5], [5]]), array([[6, 7, 8, 9], [6, 7, 8, 9]])]
纵向拆分函数:vsplit()
方式同横向拆分
代码示例:
import numpy as np m = np.array([[1,1],[2,2],[3,3],[4,4],[5,5],[6,6]]) print(np.vsplit(m,3))运行结果:
[array([[1, 1], [2, 2]]), array([[3, 3], [4, 4]]), array([[5, 5], [6, 6]])]