Are tuples more efficient than lists in Python?

Question

Is there any performance difference between tuples and lists when it comes to instantiation and retrieval of elements?

Answer 1

The main reason for Tuple to be very efficient in reading because ts immutable.

why immutable objects are easy to read?

The reason is tuples can be stored in the memory cache, unlike lists. The program always read from the lists memory location as it is mutable(Can change any time)

Answer 2

In general, you might expect tuples to be slightly faster. However you should definitely test your specific case (if the difference might impact the performance of your program -- remember "premature optimization is the root of all evil").

Python makes this very easy: timeit is your friend.

$ python -m timeit "x=(1,2,3,4,5,6,7,8)"
10000000 loops, best of 3: 0.0388 usec per loop

$ python -m timeit "x=[1,2,3,4,5,6,7,8]"
1000000 loops, best of 3: 0.363 usec per loop

and...

$ python -m timeit -s "x=(1,2,3,4,5,6,7,8)" "y=x[3]"
10000000 loops, best of 3: 0.0938 usec per loop

$ python -m timeit -s "x=[1,2,3,4,5,6,7,8]" "y=x[3]"
10000000 loops, best of 3: 0.0649 usec per loop

So in this case, instantiation is almost an order of magnitude faster for the tuple, but item access is actually somewhat faster for the list! So if you're creating a few tuples and accessing them many many times, it may actually be faster to use lists instead.

Of course if you want to change an item, the list will definitely be faster since you'd need to create an entire new tuple to change one item of it (since tuples are immutable).