How can I get a callable factory for a defaultdict to allow populating it with a comprehension? I think it's probably not possible, but I can't think of a good reason why? >>> def foo(*ar...

I have this: >>> sum( i*i for i in xrange(5)) My question is, in this case am I passing a list comprehension or a generator object to sum ? How do I tell that? Is there a general rule a...

On several occasions I've wanted python syntax for short-circuiting list comprehensions or generator expressions. Here is a simple list comprehension, and the equivalent for loop in python:...

I am using Python to parse a large file. What I want to do is If condition =True append to list A else append to list B I want to use generator expressions for this - to save memory. I am put...

Possible Duplicate: Do python's variable length arguments (*args) expand a generator at function call time? Let's say you have a function like this: def give_me_many(*elements): ...

I was answering this question, I preferred generator expression here and used this, which I thought would be faster as generator doesn't need to create the whole list first: >>> lis=[['a'...

In the following: name = 'TODD' chars = set('AEIOU') for ii in range(-1, int(math.copysign(len(name) + 1, -1)), -1): if any((cc in chars) for cc in name[ii]): print 'Found' else: print 'Not Fo...

In Python, is there any way to write this list comprehension without the "x in" variable (since it is left completely unused)? Same applies to a generator expression. I doubt this comes up very oft...

I want to determine if a list contains a certain string, so I use a generator expression, like so: g = (s for s in myList if s == myString) any(g) Of course I want to inline this, so I do: any(...

I can use if and for in list comprehensions/generator expressions as list(i for i in range(100) if i*i < 30) I know this is not the most efficient but bear with me as the condition could be m...

print max(3 for i in range(4)) #output is 3 Using Python 2.6 The 3 is throwing me off, heres my attempt at explaining whats going on. for i in range(4) makes a loop that loops 4 times, incremen...

I was trying to find the quickest way to count the number of items in a list matching a specific filter. In this case, finding how many odd numbers there are in a list. While doing this, I was sur...

Is there, in Django, a standard way to write complex, custom filters for QuerySets? Just as I can write MyClass.objects.all().filter(field=val) I'd like to do something like this : MyClass.ob...

The following test fails: #!/usr/bin/env python def f(*args): """ >>> t = 1, -1 >>> f(*map(lambda i: lambda: i, t)) [1, -1] >>> f(*(lambda: i for i in t)) # -...