tips for this exercise?

Brian Quinlan brian at sweetapp.com
Tue Mar 28 22:30:03 CEST 2006

```John Salerno wrote:
> I'm working on another exercise now about generating random numbers for
> the lottery. What I want to do is write a function that picks 5 random
> numbers from 1-53 and returns them. Here's what I have so far:
>
> numbers = range(1, 54)
>
> def genNumbers():
>      for x in range(5):
>      	fiveNumbers = []
>      	number = random.choice(numbers)
>      	numbers.remove(number)
>      	fiveNumbers = fiveNumbers.append(number)
>      	return fiveNumbers
>
> Other than being sort of ugly, this also has the side effect of actually
> editing the original list, which I don't want since I will want to
> generate more than one set of numbers.
>
> Is there a better way to extract a certain number of items from a list
> (so maybe I don't need the for loop)? Is a list even the right type to
> use, since it gets edited in place? Perhaps a set?

I would just write the function like this:

def genNumbers():
shuffle_nums = numbers[:]    # copy the list to preserve the orginal
# order (if it matters)
random.shuffle(shuffle_nums) # shuffle the entire list
return shuffle_nums[:5]      # return the first 5 elements

Cheers,
Brian

```