When I run the following snippet the "for" loop exits
early, not examining every item in the "lines" list. 
It will only print part of the list, i.e., only
approximately 65% of any list I use is printed.  (E.g.,
a list of 100 items only about 65 is printed)

If I wrap the for statement in another for statement
with a range() operator it works.

I'm pretty new to scripting, so I'm sure there's a
better way to do what I'm trying; but this seems like a
 bug.

Thanks for your help,

=========================

count = 0
lines =
["1","2","3","4","5","6","7","8","9","10","11","12","13","14","15","16"]
def getnextline():
		l = lines.pop()
		l = l.strip()
		return l
for x in lines:
	count += 1
	newline = "%s,%s,\n" % (getnextline(),getnextline())
	print count, ":", newline	

Output:
---------
1 : 16,15,

2 : 14,13,

3 : 12,11,

4 : 10,9,

5 : 8,7,

6 : 6,5,

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Sorry, the bug is in your code (the for-loop is looping 
over a list that is being mutated by pops).  I recommend 
posting on comp.lang.python or to the python-tutor list to 
get feedback on how to write this correctly.

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Changed "group" to not-a-bug.