VERY basic python string

Question

I'm very new and just came across an exercise which asks:

Given a string and a non-negative integer n, return a larger string that is n copies of the original string.

I answered:

def string_times(str, n):
    return(str * n)

and passed all tests. The solution provided:

def string_times(str, n):
     result = ""
     for i in range(n):  # range(n) is [0, 1, 2, .... n-1]
         result = result + str  # could use += here
     return result

My question is: is there any reason why my simpler solution won't work in some cases, or is it just a matter of a more experienced programmer overthinking things?

Answer 1

Your answer is correct, but the exercise probably wanted to reveal other concepts such as for loops and string concatenation using + and +=.

That said, I'd like to add to the stated solution that it is a better practice to use an underscore when you don't really need the loop variable. It's a way of telling future programmers you are not using the variable anywhere in the loop.

It's also better to use xrange if you don't actually need a list (generated by range). You can try in the interpreter range(1000000) and xrange(1000000) to see the immediate difference. xrange is actually a generator, making it a lot more memory efficient.

in python 3, range returns a generator by default

# changed i to an underscore, using xrange instead of range
for _ in xrange(n):  # xrange(n) *generates* 0, 1, 2 ... n-1