If not, what is the best way to do this?
Right now I'm doing (for a django project):
if not 'thing_for_purpose' in request.session:
request.session['thing_for_purpose'] = 5
but its pretty awkward. In Ruby it would be:
request.session['thing_for_purpose'] ||= 5
which is much nicer.
Jon-Eric's answer's is good for dicts, but the title seeks a general equivalent to ruby's ||= operator.
A common way to do something like ||= in Python is
x = x or new_value
Setting a default makes sense if you're doing it in a middleware or something, but if you need a default value in the context of one request:
request.session.get('thing_for_purpose', 5) # gets a default
bonus: here's how to really do an ||= in Python.
def test_function(self, d=None):
'a simple test function'
d = d or {}
# ... do things with d and return ...