keras将标签转化为one-hot

• 将标签转换为onehot

from keras.utils import to_categorical
y = numpy.array([0, 1, 5, 2, 3])
onehot = to_categorical(y, num_classes=6)
print(onehot)

# output
[[1. 0. 0. 0. 0. 0.]
 [0. 1. 0. 0. 0. 0.]
 [0. 0. 0. 0. 0. 1.]
 [0. 0. 1. 0. 0. 0.]
 [0. 0. 0. 1. 0. 0.]]

• 将onehot转换回标签（通常在测试时用到）

de_onehot = numpy.argmax(onehot, axis=1)
print(y)

# output
[0 1 5 2 3]