How to be a happy programmer (with Python) ? 2/3

In the series of the Python “features” that makes me happy last time i began with two concepts, the with statement and the list comprehensions, now i'm going to talk about Multiple assignments and the import aliases.

It's a simple idea that lets you return a series of value and on the other end assign those multiple values at the same time, example when you're splitting a string or extracting groups from a regular expression :

[sourcecode language=”python”]

split_me =“here,we, are,again”
# splitting we’ll get a list of values
split_me.split(",")
[‘here’, ‘we’, ’ are’, ‘again’]
# if you don’t know the number of values you’re going to have
# you can’t use this features, example :
(start,end) = split_me.split(",")
Traceback (most recent call last):
File “”, line 1, in
ValueError: too many values to unpack
# but if you know that there’s going to be n values :
(start,end) = split_me.split(" “)
start
‘here,we,’
end
‘are,again’
[/sourcecode]

It means what it says, when you import a library or module, you can use aliases, example in Django for shortcuts :

[sourcecode language=”python”]
# this is extracted from my own code :
from django.http import HttpResponse, HttpResponseRedirect as redirect
from django.shortcuts import render_to_response as render
[/sourcecode]

I won't start to talk about the standard library as a whole, or libs like Numpy, Scypy, scikit-learn, .... that makes it so easy to just think in Python.

And you ? What are the Python constructs (2.x or 3.x) that makes you feel happy and efficient at the end of the day ?