Trying To Catch Invalid User Input

Victor Subervi victorsubervi at gmail.com
Mon Aug 24 16:17:04 CEST 2009


That's nice. Thanks!
V

On Sun, Aug 23, 2009 at 5:02 PM, Dennis Lee Bieber <wlfraed at ix.netcom.com>wrote:

> On Sun, 23 Aug 2009 10:04:57 -0500, Victor Subervi
> <victorsubervi at gmail.com> declaimed the following in
> gmane.comp.python.general:
>
> > Hi;
> > I have the following:
> >
> > style = raw_input('What style is this? (1 = short, 2 = long): ')
> > flag = 0
> > while flag == 0:
> >   if (style != 1) or (style != 2):
> >     style = raw_input('There was a mistake. What style is this? (1 =
> short,
> > 2 = long): ')
> >   else:
> >     flag = 1
> >
>         Ugh... Unless you are using an archaic version of Python, the
> language has support for booleans...
>
> done = False
> while not done:
>        ...
>        done = True
>
>
>        You fail to convert the character input from raw_input into an
> integer for comparison... Oh, and you say the input is wrong if it is
> NOT 1 OR NOT 2... 1 is not 2, and 2 is not 1, so... even if you did
> convert to an integer, it would be rejected.
>
>        Consider:
>
> -=-=-=-=-=-=-=-
> while True:
>    charin = raw_input("What style is this? (1: short, 2: long): ")
>    try:
>        style = int(charin)
>    except:             #I know, should not use naked except clause
>        print ("The input '%s' is not a valid integer value; try again"
>                % charin)
>    else:
>        if style in (1, 2): break
>        print ("The input value '%s' is not in the valid range; try
> again"
>               % style)
> -=-=-=-=-=-=-=-
> {Watch out for line wraps}
> Works in Python 2.5
>
> E:\UserData\Dennis Lee Bieber\My Documents>python Script1.py
> What style is this? (1: short, 2: long): ab1
> The input 'ab1' is not a valid integer value; try again
> What style is this? (1: short, 2: long): 1a
> The input '1a' is not a valid integer value; try again
> What style is this? (1: short, 2: long): 12
> The input value '12' is not in the valid range; try again
> What style is this? (1: short, 2: long): 2
>
> E:\UserData\Dennis Lee Bieber\My Documents>
>
> --
>        Wulfraed         Dennis Lee Bieber               KD6MOG
>        wlfraed at ix.netcom.com   HTTP://wlfraed.home.netcom.com/
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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