variable-scope-in-list-comprehension-vs-generator-expression.py

"""
TL;DR for http://www.librador.com/2014/07/10/Variable-scope-in-list-comprehension-vs-generator-expression/

In Python 2, a list comprehension "leaks" its variable into the current scope,
while a generator expression does not.
This means that there's a subtle difference between
`list(x for x in y)` and `[x for x in y]`.

Example:

>>> [a for a in (1, 2, 3)]
[1, 2, 3]
>>> a
3

>>> list(b for b in (1, 2, 3))
[1, 2, 3]
>>> b
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'b' is not defined

In Python 3, the variable doesn't leak in list comprehensions either.
"""