resolving map function issue in python 3 vs python 2

Question

I'm interested in functional programming with python and am working through Mary Rose Cook's blog post A practical introduction to functional programming.

Apparently, it was written in python 2 as this:

name_lengths = map(len, ["Mary", "Isla", "Sam"])

print name_lengths
# => [4, 4, 3]

in Python 3 yields this:

<map object at 0x100b87a20>

I have two questions:

1. Why is this is so?
2. Other than converting the map object to a list and then use numpy, are there any other solutions?

Answer 1

As documented, in the migration guide,

In Python 2 map() returns a list while in Python 3 it returns an iterator.

Python 2:

Apply function to every item of iterable and return a list of the results.

Python 3:

Return an iterator that applies function to every item of iterable, yielding the results.

Python 2 always does the equivalent of list(imap(...)), Python 3 allows for lazy evaluation.