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Decrease for loop by one

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  Decrease for loop by one Milter Skyler <matt17@gmail.com> - 2013-01-23 20:39 -0800
    Re: Decrease for loop by one Chris Angelico <rosuav@gmail.com> - 2013-01-24 15:59 +1100
      Re: Decrease for loop by one Milter Skyler <matt17@gmail.com> - 2013-01-23 21:10 -0800
      Re: Decrease for loop by one Milter Skyler <matt17@gmail.com> - 2013-01-23 21:10 -0800

#37534 — Decrease for loop by one

I'm using this code with Sikuli so thats why I have click()
    for x in range(0,10):
        decimal_value = random.randint(1,12)
        if myList.count(decimal_value) < 1:
            egg = 'A%d.png' % (decimal_value)
            egg = wait(egg)
            click(egg.getCenter().offset(random.randint(-10,10), random.randint(-10,10)))
            myList.append(decimal_value)

        else:
            print x
            x-1 = x
            print x

I made an array to check if the random integer already exists and then I send it to the else statement at which point I want to decrease x by 1 so that it doesn't count as one of the loops. In other languages this works but it just comes up with the output:

3
2

9
8

10
9

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#37536

On Thu, Jan 24, 2013 at 3:39 PM, Milter Skyler <matt17@gmail.com> wrote:
> I made an array to check if the random integer already exists and then I send it to the else statement at which point I want to decrease x by 1 so that it doesn't count as one of the loops. In other languages this works...

A Python 'for' loop doesn't behave like that; you can't just edit the
loop counter. But take a step back: what are you actually trying to
accomplish? As I see it, you're trying to pick ten unique random
values in the range 1-12 inclusive. Try this:

random.sample(range(1,13),10) # note that range() stops *before* its second arg

That'll give you a list of those integers, and it's a lot safer and
more reliable than the try-fail-retry method. Your loop can become:

    for decimal_value in random.sample(range(1,13),10):
            egg = 'A%d.png' % (decimal_value)
            egg = wait(egg)
            click(egg.getCenter().offset(random.randint(-10,10),
random.randint(-10,10)))

By the way, this line simply won't work:

x-1 = x

I think you mean:

x = x-1

But I strongly suggest you copy and paste directly rather than retype;
it's less error-prone.

Hope that helps!

ChrisA

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#37539

On Wednesday, January 23, 2013 9:59:13 PM UTC-7, Chris Angelico wrote:
> On Thu, Jan 24, 2013 at 3:39 PM, Milter Skyler <> wrote:
> 
> > I made an array to check if the random integer already exists and then I send it to the else statement at which point I want to decrease x by 1 so that it doesn't count as one of the loops. In other languages this works...
> 
> 
> 
> A Python 'for' loop doesn't behave like that; you can't just edit the
> 
> loop counter. But take a step back: what are you actually trying to
> 
> accomplish? As I see it, you're trying to pick ten unique random
> 
> values in the range 1-12 inclusive. Try this:
> 
> 
> 
> random.sample(range(1,13),10) # note that range() stops *before* its second arg
> 
> 
> 
> That'll give you a list of those integers, and it's a lot safer and
> 
> more reliable than the try-fail-retry method. Your loop can become:
> 
> 
> 
>     for decimal_value in random.sample(range(1,13),10):
> 
>             egg = 'A%d.png' % (decimal_value)
> 
>             egg = wait(egg)
> 
>             click(egg.getCenter().offset(random.randint(-10,10),
> 
> random.randint(-10,10)))
> 
> 
> 
> By the way, this line simply won't work:
> 
> 
> 
> x-1 = x
> 
> 
> 
> I think you mean:
> 
> 
> 
> x = x-1
> 
> 
> 
> But I strongly suggest you copy and paste directly rather than retype;
> 
> it's less error-prone.
> 
> 
> 
> Hope that helps!
> 
> 
> 
> ChrisA

Thanks! That worked perfect, I was trying to figure that out but instead I just went down the hard route I went down.

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#37540

On Wednesday, January 23, 2013 9:59:13 PM UTC-7, Chris Angelico wrote:
> On Thu, Jan 24, 2013 at 3:39 PM, Milter Skyler <> wrote:
> 
> > I made an array to check if the random integer already exists and then I send it to the else statement at which point I want to decrease x by 1 so that it doesn't count as one of the loops. In other languages this works...
> 
> 
> 
> A Python 'for' loop doesn't behave like that; you can't just edit the
> 
> loop counter. But take a step back: what are you actually trying to
> 
> accomplish? As I see it, you're trying to pick ten unique random
> 
> values in the range 1-12 inclusive. Try this:
> 
> 
> 
> random.sample(range(1,13),10) # note that range() stops *before* its second arg
> 
> 
> 
> That'll give you a list of those integers, and it's a lot safer and
> 
> more reliable than the try-fail-retry method. Your loop can become:
> 
> 
> 
>     for decimal_value in random.sample(range(1,13),10):
> 
>             egg = 'A%d.png' % (decimal_value)
> 
>             egg = wait(egg)
> 
>             click(egg.getCenter().offset(random.randint(-10,10),
> 
> random.randint(-10,10)))
> 
> 
> 
> By the way, this line simply won't work:
> 
> 
> 
> x-1 = x
> 
> 
> 
> I think you mean:
> 
> 
> 
> x = x-1
> 
> 
> 
> But I strongly suggest you copy and paste directly rather than retype;
> 
> it's less error-prone.
> 
> 
> 
> Hope that helps!
> 
> 
> 
> ChrisA

Thanks! That worked perfect, I was trying to figure that out but instead I just went down the hard route I went down.

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