Create a slice using a tuple

Question

Is there any way in python to use a tuple as the indices for a slice? The following is not valid:

>>> a = range(20) >>> b = (5, 12)   # my slice indices >>> a[b]          # not valid >>> a[slice(b)]   # not valid >>> a[b[0]:b[1]] # is an awkward syntax [5, 6, 7, 8, 9, 10, 11] >>> b1, b2 = b >>> a[b1:b2]      # looks a bit cleaner [5, 6, 7, 8, 9, 10, 11] 

It seems like a reasonably pythonic syntax so I am surprised that I can't do it.

Answer 1

You can use Python's *args syntax for this:

>>> a = range(20) >>> b = (5, 12) >>> a[slice(*b)] [5, 6, 7, 8, 9, 10, 11] 

Basically, you're telling Python to unpack the tuple b into individual elements and pass each of those elements to the slice() function as individual arguments.

Answer 2

How about a[slice(*b)]?

Is that sufficiently pythonic?