Skip to main content

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Required fields*

Create list of single item repeated N times

I want to create a series of lists, all of varying lengths. Each list will contain the same element e, repeated n times (where n = length of the list).

How do I create the lists, without using a list comprehension [e for number in range(n)] for each list?

Answer*

Cancel
2
  • 1
    If you are already using Numpy for other reasons, this one is good to know (but trivial enough to be obvious to those who need it). For solving the problem from scratch, adding a huge third-party library just for this is silly at best and irresponsible at worst. Commented Aug 26, 2023 at 18:10
  • what's less obvious is the massive speedup that you get. I would have imagined python to optimise these types of operations somehow, but no! (see the answer after my revision has been added). Commented Jan 21, 2024 at 21:06