转载于：python numpy 矩阵二值化

矩阵

np.random.seed(0)
np.set_printoptions(precision=3)
a = np.random.rand(4, 4)
threshold, upper, lower = 0.5, 1, 0

结果是这样：

array([[ 0.02 , 0.833, 0.778, 0.87 ],
       [ 0.979, 0.799, 0.461, 0.781],
       [ 0.118, 0.64 , 0.143, 0.945],
       [ 0.522, 0.415, 0.265, 0.774]])

方法一

a[a>threshold] = upper
a[a<=threshold] = lower

方法二

np.where(a>threshold, upper, lower)

结果

array([[0, 1, 1, 1],
       [1, 1, 0, 1],
       [0, 1, 0, 1],
       [1, 0, 0, 1]])