3 ms·

There is however no benefit in replacing a mylist.sort() with mylist = sorted(mylist), in fact it will use more memory. Isn't that kind of a deal-breaker?

probably 14y ago
And sorted() and reversed() behave differently (return different object classes) while mylist.sort() and mylist.reverse() do. In that way it's also confusing. The modify-in-place method does seems more natural when you do want the destructive updating case.
sophacles 14y ago
It depends on you case. If you are doing: slist = list(mylist) #create new copy of the list slist.sort() #sort the list use_sorted_list(slist) The use of sorted is more more convenient, and really doesn't use more memory (since the memory from that statement you quoted is for the list copy). More usefully: sorted will take anything that is iterable, allowing you to write simpler code, rather than testing for various types and dealing with them in type specific ways.
dbecker 14y ago
The benefit is only lost if you want to store the sorted mylist. However, sorted() is useful if you want to create a list, sort it, use it, and throw it away... all in a single line. The blog gives an example where a file is read, sorted and transformed. If he loaded the file to a list and sorted that list before transforming it, there would be an unnecessary copy of the list sitting around consuming memory.
tetha 14y ago
He doesn't do a clean comparision. If you have a list of data and need this data in a specific order and coincidentially iterate over this list every once in a while, then sorted will be less efficient, because you can sort in-place once. If you have a list of data and you want to iterate over it in a specific order just this single time, you will need to spend a linear amount of memory to sort the list and then iterate over it. In the first case, sorted() is not useful, because .sort() sorts in-place without additional memory overhead. In the second case, copy/.sort is required and just requires more code for pretty much the same effect. In this case, sorted() is just as bad as the alternative, but shorter.
VMG 14y ago
sometimes clarity and elegance win over performance
mattdeboard 14y ago
Not at all. With .sort() you're suddenly injecting state into your code, with all the complexity that implies.

probably 14y ago

And sorted() and reversed() behave differently (return different object classes) while mylist.sort() and mylist.reverse() do. In that way it's also confusing. The modify-in-place method does seems more natural when you do want the destructive updating case.

sophacles 14y ago

It depends on you case. If you are doing: slist = list(mylist) #create new copy of the list slist.sort() #sort the list use_sorted_list(slist) The use of sorted is more more convenient, and really doesn't use more memory (since the memory from that statement you quoted is for the list copy). More usefully: sorted will take anything that is iterable, allowing you to write simpler code, rather than testing for various types and dealing with them in type specific ways.

dbecker 14y ago

The benefit is only lost if you want to store the sorted mylist. However, sorted() is useful if you want to create a list, sort it, use it, and throw it away... all in a single line. The blog gives an example where a file is read, sorted and transformed. If he loaded the file to a list and sorted that list before transforming it, there would be an unnecessary copy of the list sitting around consuming memory.

tetha 14y ago

He doesn't do a clean comparision. If you have a list of data and need this data in a specific order and coincidentially iterate over this list every once in a while, then sorted will be less efficient, because you can sort in-place once. If you have a list of data and you want to iterate over it in a specific order just this single time, you will need to spend a linear amount of memory to sort the list and then iterate over it. In the first case, sorted() is not useful, because .sort() sorts in-place without additional memory overhead. In the second case, copy/.sort is required and just requires more code for pretty much the same effect. In this case, sorted() is just as bad as the alternative, but shorter.

VMG 14y ago

sometimes clarity and elegance win over performance

mattdeboard 14y ago

Not at all. With .sort() you're suddenly injecting state into your code, with all the complexity that implies.