Efficient iteration with comprehensions and generators

In this section, we will explore a few simple strategies to speed up Python loops using comprehensions and generators. In Python, comprehension and generator expressions are fairly optimized operations and should be preferred in place of explicit for loops, as they are designed to avoid many unnecessary computational overheads during their construction. Another reason to use this construct is readability; even if the speedup over a standard loop is modest, the comprehension and generator syntax is more compact and (most of the time) more intuitive.

In the following example, we can see that both the list comprehension and generator expressions are faster than an explicit loop when combined with the sum function:

    def loop(): 
        res = [] 
        for i in range(100000): 
        ...