"Katt" <the_only_kat...@verizon.net> wrote
Just a newbie question, but when would you test for an empty list?
When you are processing a list such that you are deleting items as you go.
When the list is empty stop processing!
And Python helps you do that by treating an empty list as a False
boolean value so you can do
while myList:
process items from myList
This will keep on processing myList until all the items have
been deleted. Note, this could be more times than the number
of items in the list...for example:
counter = 0
myList = [12,24]
nines = []
while myList:
counter += 1
print "iteration number", counter
index = 0
while index < len(myList): # copes with disappearing members
if myList[index] % 9 == 0: # is it divisible by 9?
nines.append(myList[index])
del(myList[index]) # remove from list
else: myList[index] -= 1
index += 1
print nines
while len(mylist) > 0:
continue program
else:
print "mylist is empty
That is the same as
while mylist:
continue program
else:
print 'mylist is empty'
HTH,
--
Alan Gauld
Author of the Learn to Program web site
http://www.alan-g.me.uk/
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