How to emulate sum() using a list comprehension?

Question

Is it possible to emulate something like sum() using list comprehension ?

For example - I need to calculate the product of all elements in a list :

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Answer 1

List comprehension always creates another list, so it's not useful in combining them (e.g. to give a single number). Also, there's no way to make an assignment in list comprehension, unless you're super sneaky.

The only time I'd ever see using list comprehensions as being useful for a sum method is if you only want to include specific values in the list, or you don't have a list of numbers:

list = [1,2,3,4,5]
product = [i for i in list if i % 2 ==0] # only sum even numbers in the list
print sum(product)

or another example":

# list of the cost of fruits in pence
list = [("apple", 55), ("orange", 60), ("pineapple", 140), ("lemon", 80)]
product = [price for fruit, price in list]
print sum(product)

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Super sneaky way to make an assignment in a list comprehension

dict = {"val":0}
list = [1, 2, 3]
product = [dict.update({"val" : dict["val"]*i}) for i in list]
print dict["val"] # it'll give you 6!

...but that's horrible :)