Don't overdo comprehensions and generators

We've seen how powerful list comprehensions and generator expressions can be. And they are, don't get me wrong, but the feeling that I have when I deal with them is that their complexity grows exponentially. The more you try to do within a single comprehension or a generator expression, the harder it becomes to read, understand, and therefore to maintain or change.

Open a Python console and type in import this, let's read the Zen of Python again, in particular, there are a few lines that I think are very important to keep in mind:

>>> import this
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.  #
Simple is better than complex.  #
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.  #
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced...