[Numpy-discussion] reshaping array question

[Sebastian Berg]

On Di, 2015-11-17 at 10:48 -0500, Neal Becker wrote:
> I have an array of shape
> (7, 24, 2, 1024)
> 
> I'd like an array of
> (7, 24, 2048)
> 
> such that the elements on the last dimension are interleaving the elements 
> from the 3rd dimension
> 

Which basically means you want to reshape with the earlier index varying
faster. This is fortran order (in the simplest case for two axes being
reshaped). So you can do:

arr.reshape((7, 24, -1), order="F")

otherwise, if order seems too confusing or dangerous. Just transpose the
two axes first:

arr_r = arr.transpose((0, 1, 3, 2))
arr_r = arr_r.reshape((7, 24, -1))

- Sebastian

> [0,0,0,0] -> [0,0,0]
> [0,0,1,0] -> [0,0,1]
> [0,0,0,1] -> [0,0,2]
> [0,0,1,1] -> [0,0,3]
> ...
> 
> What might be the simplest way to do this?
> 
> ------------
> A different question, suppose I just want to stack them
> 
> [0,0,0,0] -> [0,0,0]
> [0,0,0,1] -> [0,0,1]
> [0,0,0,2] -> [0,0,2]
> ...
> [0,0,1,0] -> [0,0,1024]
> [0,0,1,1] -> [0,0,1025]
> [0,0,1,2] -> [0,0,1026]
> ...
> 
> 
> 
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