113
votes

Possible Duplicate:
About python's built in sort() method

Name says it all.

I'm trying to explain to someone why they should use Python's builtin sorted() function instead of rolling their own, and I realized I have no idea what algorithm it uses.

If it matters, we're talking python 2.7

3
stackoverflow.com/questions/1517347/… Question has been answered here. It uses Timsort - Aharpe
For others who are curious, this article is great: corte.si//posts/code/timsort/index.html - Hartley Brody

3 Answers

204
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Python uses an algorithm called Timsort:

Timsort is a hybrid sorting algorithm, derived from merge sort and insertion sort, designed to perform well on many kinds of real-world data. It was invented by Tim Peters in 2002 for use in the Python programming language. The algorithm finds subsets of the data that are already ordered, and uses the subsets to sort the data more efficiently. This is done by merging an identified subset, called a run, with existing runs until certain criteria are fulfilled. Timsort has been Python's standard sorting algorithm since version 2.3. It is now also used to sort arrays in Java SE 7, and on the Android platform.

11
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The sort algorithm is called Timsort. See timsort

8
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