regarding the usage of crop_data = data[:,offset1:-offset1, offset2:-offset2]

[winecoding]

While reading an existing software, I once read the following code segment

crop_data = data[:,offset1:-offset1, offset2:-offset2]

I think crop_data will be a slice of data. However, I am not clear how does this slice,

offset1:-offset1

, work?  Besides, I am not sure which dimensions of original data should be changed.

For instance, I tried an array of data, which is of shape 

(1,300,300,1)

. After setting up 

offset1=0   and offset2=0

I found the

crop_data

resulted from this

crop_data = data[:,offset1:-offset1, offset2:-offset2]

will have shape 

(1,0,0,1)

. I do not know why is that?

[metulburr]

crop_data = data[:,offset1:-offset1, offset2:-offset2]

This doesnt look like proper slicing at all. With this code you should get an error such as

>>> 'sdfgsdfsgshdffsfsdfdhdfghajadjhg'[:,5:-5,-10:-10]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: string indices must be integers, not tuple