mxnet-索引

The basic slice syntax is?i:j:k?where?i?is the starting index,?j?is the stopping index, and?k?is the step (). This selects the?m?elements (in the corresponding dimension) with index values?i,?i + k, ...,?i + (m - 1) k?where??and?q?and?r?are the quotient and remainder obtained by dividing?j - i?by?k:?j - i = q k + r, so that?i + (m - 1) k < j.

 # -*- coding: utf-8 -*-"""Spyder EditorThis is a temporary script file."""import mxnet as mximport numpy as npimport pickle as pklimport timex = mx.nd.zeros((2,3))x[:] = 1print x.asnumpy()x[:,1:2] = 2print x.asnumpy()x[1:2,1:] = 3print x.asnumpy()x[1:,0:2] = mx.nd.zeros((1,2))print x.asnumpy()x[1,2] = 4print x.asnumpy()x[[0], [1, 2]] = 5print x.asnumpy()x[::-1, 0:2:2] = [6]print x.asnumpy()

[[1. 1. 1.]
?[1. 1. 1.]]
[[1. 2. 1.]
?[1. 2. 1.]]
[[1. 2. 1.]
?[1. 3. 3.]]
[[1. 2. 1.]
?[0. 0. 3.]]
[[1. 2. 1.]
?[0. 0. 4.]]
[[1. 5. 5.]
?[0. 0. 4.]]
[[6. 5. 5.]
?[6. 0. 4.]]

 # -*- coding: utf-8 -*-"""Spyder EditorThis is a temporary script file."""import mxnet as mximport numpy as npx = mx.nd.arange(12)print xprint x[3:10:3]print x[10:3:-3]print x[::3]print x[::-3]

[ 0. ?1. ?2. ... ?9. 10. 11.]
<NDArray 12 @cpu(0)>

[3. 6. 9.]
<NDArray 3 @cpu(0)>

[10. ?7. ?4.]
<NDArray 3 @cpu(0)>

[0. 3. 6. 9.]
<NDArray 4 @cpu(0)>

[11. ?8. ?5. ?2.]
<NDArray 4 @cpu(0)>

# -*- coding: utf-8 -*-"""Spyder EditorThis is a temporary script file."""import mxnet as mximport numpy as npx = mx.nd.arange(0,6).reshape((2,3))print x.asnumpy()print x[1].asnumpy()y = x[0:1]y[:] = 2print yprint x.asnumpy()x = mx.nd.arange(0, 8, dtype=‘int32‘).reshape((2, 2, 2))print x[[0, 1]]print x[1:, [0, 1]]y = np.array([0, 1], dtype=‘int32‘)print x[1:, y]y = mx.nd.array([0, 1], dtype=‘int32‘)print x[1:, y]

_register_converters
[[0. 1. 2.]
?[3. 4. 5.]]
[3. 4. 5.]

[[2. 2. 2.]]
<NDArray 1x3 @cpu(0)>
[[2. 2. 2.]
?[3. 4. 5.]]

[[[0 1]
? [2 3]]

?[[4 5]
? [6 7]]]
<NDArray 2x2x2 @cpu(0)>

[[[4 5]
? [6 7]]]
<NDArray 1x2x2 @cpu(0)>

[[[4 5]
? [6 7]]]
<NDArray 1x2x2 @cpu(0)>

[[[4 5]
? [6 7]]]
<NDArray 1x2x2 @cpu(0)>

?

?

?

?

?

==

 # -*- coding: utf-8 -*-"""Spyder EditorThis is a temporary script file."""import mxnet as mximport numpy as npx = mx.nd.arange(0,6).reshape(2,3)print xy = x.reshape(3,2)print yy = x.reshape(3,-1)print yy = x.reshape(3,2)print yy = x.reshape(-3)print yy[:] = -1print x

[[0. 1. 2.]
?[3. 4. 5.]]
<NDArray 2x3 @cpu(0)>

[[0. 1.]
?[2. 3.]
?[4. 5.]]
<NDArray 3x2 @cpu(0)>

[[0. 1.]
?[2. 3.]
?[4. 5.]]
<NDArray 3x2 @cpu(0)>

[[0. 1.]
?[2. 3.]
?[4. 5.]]
<NDArray 3x2 @cpu(0)>

[0. 1. 2. 3. 4. 5.]
<NDArray 6 @cpu(0)>

[[-1. -1. -1.]
?[-1. -1. -1.]]
<NDArray 2x3 @cpu(0)>

mxnet-索引

原文地址：http://blog.51cto.com/13959448/2316501