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Re: Variables in a loop, Newby question

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vanommen.robert@gmail.com wrote:

> Hello, for the first time I'm trying te create a little Python program.
> (on a raspberri Pi)
> 
> I don't understand the handling of variables in a loop with Python.
> 
> 
> Lets say i want something like this.
> 
> x = 1
> while x <> 10
> var x = x
> x = x + 1
> 
> The results must be:
> 
> var1 = 1
> var2 = 2
> 
> enz. until var9 = 9
> 
> How do i program this in python?

You are trying to generate a variable name programatically. While this is 
possible in Python

>>> x = 1
>>> while x != 10:
...     exec("var{} = x".format(x))
...     x = x + 1
... 
>>> var1
1
>>> var7
7

this is a really bad idea that you probably picked up from old code in a 
lesser language. Don't do it that way!

In Python you should use a dict or a list, for example:

>>> var = [] # an empty list
>>> x = 0
>>> while x < 10:
...     var.append(x) # append an item to the list
...     x += 1
... 
>>> var
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

This can be simplified to a single line:

>>> var = list(range(10))

A few usage examples:

>>> var[0]
0
>>> var[9]
9
>>> var[10]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: list index out of range

As you can see list indices are zero-based. A list of length 10 has items 0 
to 9.

>>> var[7] += 42
>>> var
[0, 1, 2, 3, 4, 5, 6, 49, 8, 9]
>>> sum(var)
87

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Variables in a loop, Newby question vanommen.robert@gmail.com - 2013-12-24 08:07 -0800
  Re: Variables in a loop, Newby question Joel Goldstick <joel.goldstick@gmail.com> - 2013-12-24 11:20 -0500
  Re: Variables in a loop, Newby question "Tobias M." <tm@tobix.eu> - 2013-12-24 17:24 +0100
  Re: Variables in a loop, Newby question Peter Otten <__peter__@web.de> - 2013-12-24 17:29 +0100
  Re: Variables in a loop, Newby question bob gailer <bgailer@gmail.com> - 2013-12-24 12:26 -0500
  Re: Variables in a loop, Newby question vanommen.robert@gmail.com - 2013-12-24 09:54 -0800
    Re: Variables in a loop, Newby question Joel Goldstick <joel.goldstick@gmail.com> - 2013-12-24 13:10 -0500
    Re: Variables in a loop, Newby question Dave Angel <davea@davea.name> - 2013-12-24 13:42 -0500
    Re: Variables in a loop, Newby question Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-25 13:35 -0500
  Re: Variables in a loop, Newby question vanommen.robert@gmail.com - 2013-12-24 10:27 -0800
    Re: Variables in a loop, Newby question Denis McMahon <denismfmcmahon@gmail.com> - 2013-12-25 02:54 +0000
      Re: Variables in a loop, Newby question Cameron Simpson <cs@zip.com.au> - 2013-12-25 16:42 +1100
        Re: Variables in a loop, Newby question Denis McMahon <denismfmcmahon@gmail.com> - 2013-12-25 15:27 +0000
          Re: Variables in a loop, Newby question Cameron Simpson <cs@zip.com.au> - 2013-12-26 12:01 +1100
          Re: Variables in a loop, Newby question Chris Angelico <rosuav@gmail.com> - 2013-12-26 12:35 +1100
            Re: Variables in a loop, Newby question Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-12-26 16:41 +1100
              Re: Variables in a loop, Newby question Dave Angel <davea@davea.name> - 2013-12-26 03:14 -0500
              Re: Variables in a loop, Newby question Chris Angelico <rosuav@gmail.com> - 2013-12-26 19:24 +1100
    Re: Variables in a loop, Newby question Peter Otten <__peter__@web.de> - 2013-12-25 15:52 +0100
    Re: Variables in a loop, Newby question Michael Torrie <torriem@gmail.com> - 2013-12-25 23:34 -0700
  Re: Variables in a loop, Newby question Larry Hudson <orgnut@yahoo.com> - 2013-12-25 00:13 -0800
  Re: Variables in a loop, Newby question vanommen.robert@gmail.com - 2013-12-27 00:53 -0800
    Re: Variables in a loop, Newby question Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-12-27 11:39 -0500

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