Average tuple of tuples

Question

How can I average, in a generic sense, the values in a tuple of tuples such that:

(1,2,3),(3,4,5)

becomes:

(2,3,4)

Solution 1

You can use zip like so:

In [1]: x = ((1, 2, 3), (4, 5, 6))

In [2]: [sum(y) / len(y) for y in zip(*x)]
Out[3]: [2, 3, 4]

---

Another method using lambda with more then 2 tuples in the tuple and resulting in float's instead of int's:

>>> x = ((10, 10, 10), (40, 55, 66), (71, 82, 39), (1, 2, 3))
>>> print tuple(map(lambda y: sum(y) / float(len(y)), zip(*x)))
(30.5, 37.25, 29.5)

Solution 2

x = ((1,2,3),(3,4,5))

from numpy import mean  # or write your own mean function
tuple(map(mean, zip(*x)))
# (2.0, 3.0, 4.0)

or:

from numpy import mean
tuple(mean(x, axis=0))

Comments

[David Robinson]

The OP mentions that the input is a "tuple of tuples", so there could be more than 2.

[David Robinson]

@Avaris: Thanks- great idea (added), though you would have to turn it to a tuple afterwards.

[l4mpi]

please don't recommend numpy without mentioning that it is not part of the standard library and has c extensions.

[David Robinson]

@l4mpi: Like I said, he could also write his own mean function.

[l4mpi]

Ah sorry, didn't read the comment. I just happen to see numpy get recommended very often for tasks where it would only be a good choice if the program already uses numpy or the input data is huge (which it doesn't seem to be in this case), without mentioning the fact that you have to install and compile it...

[Baz]

This is a python question.