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Python Python Sequences Sequence Operations Slices

Natalie Heyde
Natalie Heyde
1,736 Points
Posted by Natalie Heyde
Natalie Heyde
1,736 Points

Why are there 4 elements in the slices.py example?

Hi,

I thought slices could only have 3 elements in them. I was wondering why in the slices.py file, there is a slice with 4 elements that looks like: nums_partial = nums[0::2] ?

Unless I'm interpreting it incorrectly, and it's more like nums_partial = nums[0:_:2], meaning a start of 0, no stop, and step of 2?

Is : a placeholder, or a separator for these values?

1 Answer

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

The colon (:) is the separator between the arguments (up to 3) in a slice.

You are correct that the expression nums[0::2] represents a start of 0, no stop, and a step of 2.

There is no limit on the number of elements a slice can contain. With these arguments, the resulting slice (nums_partial) will contain half as many elements as the original (nums) has.