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
