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Tag: slice

Retrieve length of slice from slice object in Python

The title explains itself, how to get 2 out of the object The documentation is somewhat confusing, or it is the wrong one https://docs.python.org/2/c-api/slice.html In particular I don’t understand what is the meaning of the output of One possible workaround is to slice a list with the slice object But this will fail for an arbitrary large slice. Thanks, I

unexpected result in numpy array slicing (view vs copy)

I’m trying to reduce the amount of copying in my code and I came across surprising behavior when dealing with numpy array slicing and views, as explained in: Scipy wiki page on copying numpy arrays I’ve stumbled across the following behavior, which is unexpected for me: Case 1.: As expected, this outputs: Case 2: When performing the slicing and addition

Python, converting a list of indices to slices

So I have a list of indices, and want to convert it to this, this will run on a large number of indices. Also, this technically isn’t for slices in python, the tool I am working with is faster when given a range compared to when given the individual ids. The pattern is based on being in a range, like

How to replace values at specific indexes of a python list?

If I have a list: And then declare two other lists: How can I take to_modify’s elements as index to indexes, then set corresponding elements in to_modify to replacements, i.e. after running, indexes should be [0,0,3,0,1,0]. Apparently, I can do this through a for loop: But is there other way to do this? Could I use operator.itemgetter somehow? Answer The

Slicing a list in Python without generating a copy

I have the following problem. Given a list of integers L, I need to generate all of the sublists L[k:] for k in [0, len(L) – 1], without generating copies. How do I accomplish this in Python? With a buffer object somehow? Answer The short answer Slicing lists does not generate copies of the objects in the list; it just

slicing a 2d numpy array

The following code: Is generating the following error message: I looked up the syntax at this link and I seem to be using the correct syntax to slice. However, when I type into the Python shell, it gives me the following output, which is clearly wrong, and is probably what is throwing the error: Can anyone show me how to

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