tips for this exercise?
Brian Quinlan
brian at sweetapp.com
Tue Mar 28 15:30:03 EST 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
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