Thanks for all the helps.
I'm not habitual for this usage of 'else',other languages seem don't
support this syntax.
i.g,writting the codes below by Perl would get an error:
# perl -le 'for $i (1..10){print $i} else{print "finished"}'
syntax error at -e line 1, near "}else"
Execution of -e aborted due to compilation errors.
2007/1/19, Diez B. Roggisch <[EMAIL PROTECTED]>:
> Jm lists wrote:
>
> > Please help with this script:
> >
> > class ShortInputException(Exception):
> > '''A user-defined exception class.'''
> > def __init__(self,length,atleast):
> > Exception.__init__(self)
> > self.length=length
> > self.atleast=atleast
> >
> > try:
> > s=raw_input('Enter something --> ')
> > if len(s)<3:
> > raise ShortInputException(len(s),3)
> > # Other work can continue as usual here
> > except EOFError:
> > print '\nWhy did you do an EOF on me?'
> > except ShortInputException,x:
> > print 'ShortInputException: The input was of length %d, was
> > expecting at least %d' %(x.length,x.atleast)
> > else:
> > print 'No exception was raised.'
> >
> >
> > My questions are:
> >
> > 1) ShortInputException,x: what's the 'x'? where is it coming?
>
> except <ExceptionSpec>, <variable>:
>
> will catch an exception of the kind specified in <ExceptionSpec> (it might
> actually be more than one), and store the exception object in the variable
> named <variable>
>
> > 2) The 'if' and 'else' are not in the same indent scope,why this can work?
>
>
> Because additionally to if, also for and try have else-clauses. The latter
> two are only being called if the body of the control structure hasn't been
> left due to "unnatural" circumstances. See this:
>
>
>
>
> for i in xrange(10):
> pass
> else:
> print "test 1"
>
> for i in xrange(10):
> break
> else:
> print "test 2"
>
> try:
> pass
> except:
> pass
> else:
> print "test 3"
>
> try:
> raise "I know I shouldn't rais strings..."
> except:
> pass
> else:
> print "test 4"
>
>
>
> It will only print
>
> test 1
> test 3
>
>
> Diez
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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