[Tutor] Why is this only catching one occurance?

You're removing stuff from something you're iterating over!
*slaps your fingers with a ruler*
Make a copy of the list!
HTH,
-Luke

Thats for this very humorous reply =D

That was supposed to say "Thanks for this" but I was in a hurry.

Anyways, here is my solution:
# Remove any copies of .hex that aren't BMC
for foundItem in directoryList:
try:
if ".hex" in foundItem.lower():
if "bmc" in foundItem.lower():
wantedList.append(foundItem)
else:
print foundItem + " removed!"
else:
wantedList.append(foundItem)
except:
print "Failed to strip excess hex files."

The problem is that when you remove the item from the list, the iterator
that is looping over the list gets confused and skips the next item.
(The iterator keeps an internal counter that is not updated when you
remove an item.) See http://effbot.org/zone/python-list.htm#modifying
for more.

The simplest fix is to use a list comprehension to create a new list
with only the elements you want, and assign it to the same name:

directoryList = [ item for item in directoryList if 'hex not in
item.lower() or 'bmc' in item.lower() ]

Note I changed the sense of the conditional because it is now selecting
items to include.

The list comp doesn't have exactly the same result as your (intended)
code, it creates a new list rather than modifying the old one in place.
Most of the time this doesn't matter but if you have other references to
dictionaryList only one will be changed.

Kent

"for" goes thru the list accessing item[0], item[1], item[2], etc. Let's
say "for" is on item[1] and you remove item[1]. All the subsequent items
"move left", so item[2] becomes item[1], item[3] becomes item[2], etc.
"for" then steps to item[2], skipping the original item[2].

There are several ways around this. The easiest is to process the list
backwards: for unWantedItem in directoryList[,,-1]:

I've tried to use your example:
for unWantedItem in directoryList[,,-1]:

but I get an error:
for unWantedItem in directoryList[,,-1]:
^
SyntaxError: invalid syntax

I understand what you are saying to do, and it makes sense, but I'm not sure
how to impliment it.

Chris:

See below.

<<SNIP>>

The problem is the commas. Python uses colons to describe slices. Try
this instead:
I think that will work for you.

Regards,

Barry
barry.carroll at psc.com
541-302-1107
________________________
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