Shriphani wrote:
> Hello,
> Would that mean that if I wanted to append all the (date, time) tuples
> to a list, I should do something like:
>
> for file in list_of_backup_files:
> some_list.append(file)
That would be one way to do it (assuming you started with some_list as
an empty list). But a faster way would be to use a list comprehension
and say
some_list = [f for f in list_of_backup_files]
> By the way I did this:
>
> def listAllbackups(filename):
> list_of_backups = glob(home+'/Desktop/backupdir/*%s*'%filename)
> for element in list_of_back:
> if element.find(file) != -1:
> date_components = element.split('-')[-4:-1]
> date = str(date_components[0]) + ":" +
> str(date_components[1]) +
> ":" + str(date_components[2])
> time = element.split('-')[-1]
> yield (date, time)
> print listAllbackups('fstab')
>
>
> I ran it in the terminal and I got:
>
> <generator object at 0x81ed58c>
>
> Why does it do that and not just print out all the values of (date,
> time)
Because the generator object returned by the function has to be used in
an iterative context to produce its values. Which is why the list
comprehension produces a list!
If you don't really want a generator then you could just rewrite the
function to return a list in the first place. You did specifically ask
"how do I use the yield statement ...". If you are going to iterate o
ver the list then a generator is typically more memory-efficient
(because it only produces one element at a time), and can do things that
a list can't (like deal with a potentially infinite sequence of results).
regards
Steve
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