Discussion on: SpeedUp Python List and Dictionary

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Replies for: @Dimitri Did you tried this - Kindly Look at the result below - @timeit def append_outside_loop(limit): nums = [] append = nums.append ...

Excellent! You took the time to verify what I was saying without giving proof - and you we right to do so!

The problem is that the last line in the second function is actually building a list.

Here's a better example:

def is_even(x):
    return x % 2 == 0

@timeit
def func1(my_list):
   """ calling append() in a loop """
    my_other_list = []
    for x in my_list:
        if is_even(x):
            my_other_list.append(x)


func1(list(range(1, 9999999)))

@timeit
def func2(my_list):
    """Saving one 'op' by not looking up the is_even 
   function every time
    """
    my_other_list = []
    func = is_even
    for x in my_list:
        if func(x):
            my_other_list.append(x)


func2(list(range(1, 9999999)))

@timeit
def func3(my_list):
    """Using list comprehensions
    """
    my_other_list = [x for x in my_list if is_even(x)]

func3(list(range(1, 9999999)))