[Numpy-discussion] simple way to denote unchanged dimension in reshape?

[Dave Hirschfeld]

Chao YUE <chaoyuejoy <at> gmail.com> writes:

> 
> 
> 
> Dear all,
> I have a simple question. Is there a way to denote the unchanged dimension 
in the reshape function? like suppose I have an array named "arr" having 
three dims with the first dimension length as 48, I want to reshape the 
first dim into 12*4, but keeping all the other dimension length unchanged. 
> 
> like when we slice the array, we can use:  arr[10:40, ... ], "...' 
represents all remaining dimesions. 
> 
> however when doing reshape, we must use:
> 
> arr.reshape(12,-1,arr.shape(1),arr.shape(2))
> 
> 
> Is there something allowing more flexible reshape, like:
> 
> arr.reshape(12,-1,...)?
> 
> thanks a lot in advance,best,
> 
> Chao
> 

For the example given the below code works:

In [1]: x = randn(48,5,4,3,2)

In [2]: x.reshape(12,-1,*x.shape[1:]).shape
Out[2]: (12L, 4L, 5L, 4L, 3L, 2L)


HTH,
Dave