numpy對於矩陣的各項操作整理
阿新 • • 發佈:2020-12-13
import numpy as np; import math; #構造矩陣 m = np.mat([[1,2,3,4],[2,2,3,4],[3,2,3,4],[4,2,3,4]]); print(m); #取第i行,從0開始計數 row1 = m[0]; print(row1); #取[i,j]元素,從0開始計數,如果是:這種形式那麼是從i開始包含i,到j截至不包含j item1 = m[0, 1]; print(item1); item2 = m[0, :]; print(item2); item3 = m[0:2, 0:3]; print(item3); #矩陣運算 n = np.mat([[5,5,5,5],[2,2,2,2]]); result = m * n.transpose(); print(result); addRes = m + m; print(addRes); subRes = m - m; print(subRes); powRes = np.power(m, 2); print(powRes); logRes = np.log(m); print(logRes); #求矩陣的行數和列數 rowM, colM = np.shape(m); rowN = np.shape(n)[0]; colN = np.shape(n)[1]; print(rowN, colN); zeros = np.zeros((4, 3)); print(zeros); ones = np.ones((4, 3)); print(ones); constantMat = np.full((4, 3), 7); print(constantMat); #建立單位矩陣 I = np.eye(2); print(I); #輸出隨機元素構成的矩陣 randomMat = np.random.random((2, 3)); print(randomMat); #矩陣拼接按行拼接row_stack,和按列拼接column_stack mn = np.row_stack((m, n)); print(mn);
出自:https://blog.csdn.net/u013476338/article/details/78568840