Robert Latest wrote:
>>From a list of strings I want to delete all empty ones. This works:
>
> while '' in keywords: keywords.remove('')
>
> However, to a long-term C programmer this looks like an awkward way of
> accomplishing a simple goal, because the list will have to be re-evaluated
> in each iteration.
you're using a quadratic algorihm ("in" is a linear search, and remove
has to move everything around for each call), and you're worried about
the time it takes Python to fetch a variable?
> Is there a way to just walk the list once and throw out unwanted
> elements as one goes along?
creating a new list is always almost the right way to do things like
this. in this specific case, filter() or list comprehensions are good
choices:
keywords = filter(None, keywords) # get "true" items only
keywords = [k for k in keywords if k]
also see:
http://effbot.org/zone/python-list.htm#modifying
</F>
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