Is there a way to do a variable assignment inside a function call in python? Something like
curr= []
curr.append(num = num/2)
Add a comment
|
3 Answers
Nopey. Assignment is a statement. It is not an expression as it is in C derived languages.
Comments
I'm pretty certain I remember one of the reasons Python was created was to avoid these abominations, instead preferring readability over supposed cleverness :-)
What, pray tell, is wrong with the following?
curr= []
num = num/2
curr.append(num)
Even if you could, side-effecting expressions are a great way to make your code unreadable, but no... Python interprets that as a keyword argument. The closest you could come to that is:
class Assigner(object):
def __init__(self, value):
self.value = value
def assign(self, newvalue):
self.value = newvalue
return self.value
# ...
num = Assigner(2)
curr = []
curr.append(num.assign(num.value / 2))
answered Jul 28, 2010 at 4:26
Michael Aaron Safyan
96k16 gold badges140 silver badges200 bronze badges
3 Comments
msw
Why, pray tell, would you even think of the above. ;)
Alex Martelli
@msw, sometimes one's transcribing a "reference algorithm" from C to Python, for example, and in a first phase of such a transcription staying as close to the structure of the C code as feasible is an excellent idea (one refactors later to make the code decent Python, faster, etc, after one has a working Python implementation of the reference algorithms). Slightly different, but not drastically so, analogous considerations, can apply in using Python to prototype code for later transcription into C: the closer to C's structure the prototype is, the easier the transcription will be.
msw
@alex, first of all, note the winky smiley
;), then note the lexical parallelism to the second sentence of paxdiablo's answer. Then note that the "because I can, but really, don't" of Mr. Safyan's answer and how it isn't anywhere close to the equivalent C-like expression. cf. en.wiktionary.org/wiki/levity