Checking list by using of exception
Gabriel Genellina
gagsl-py2 at yahoo.com.ar
Fri Jun 13 05:34:25 EDT 2008
En Fri, 13 Jun 2008 04:37:44 -0300, Nader <n.emami at gmail.com> escribió:
> Hello,
>
> I read some files name from a directory and then I put these name in a
> list. I will check whether it is empty or not, and I would do it with
> an exception. With if statement it is very simple:
>
> If list_of_files != "" : # this can be if list_of_files !=
> []:
> get the files
> elas:
> there is no file
If it is simple, just do it! Why do you want to make things more
complicated? This would be enough:
if list_of_files:
get_the_files(list_of_files)
else:
print "there is no file"
(a list has a false boolean value when it is empty)
> But with exception, I can write something as:
>
> try:
> list_of_files != []
> get the files
> except ValueError:
> Print " there is no file"
>
> What can the first statement be inside 'try' if I don't want to use if
> statement?
If you insist on using an exception (and assuming list_of_files is
actually a list, not a string or other kind of sequence):
try:
list_of_files[0]
except IndexError:
...no files...
This way you're checking that list_of_files contains at least one element.
But I would not reccomend it.
--
Gabriel Genellina
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