Numpy 矩阵简单操作

test = np.array([[12,23,34], [21,32,43]])
print(test.shape, 'n', test, 'n')
'''
(2, 3)
 [[12 23 34]
 [21 32 43]]
'''


# test[:, 0] = test[:, 0] - 10
# test[:, 1] = test[:, 1] - 20
# test[:, 2] = test[:, 2] - 30
test -= 20
print(test.shape, 'n', test, 'n')
'''
(2, 3)
 [[-8  3 14]
 [ 1 12 23]]
'''

print(test<0)
test[test < 0] = 0
print(test, 'n')
'''
[[ True False False]
 [False False False]]
[[ 0  3 14]
 [ 1 12 23]]
'''

print(test[:, 0] > 1)
test[test[:, 0] > 1, 0] = 1
print(test, 'n')
'''
[False False]
[[ 0  3 14]
 [ 1 12 23]]
'''

print(test[:, 1] > 5)
test[test[:, 1] > 5, 1] = 5
print(test, 'n')
'''
[False  True]
[[ 0  3 14]
 [ 1  5 23]]
'''

print(test[:, 2] > 10)
test[test[:, 2] > 10, 2] = 10
print(test, 'n')
'''
[ True  True]
[[ 0  3 10]
 [ 1  5 10]]
'''