My code has a lot of while loops of the following format:
while True:
...
if <condition>: break
The danger with such a code is that it might go to an infinite loop
- if the <condition> never occurs.
Is there a way - a python trick - to have a check such that if the
loop goes for more than x number of steps, it will cause an exception?
I do understand that we can use the code like -
i = 0
while True:
i++
if i > 200: raise infinite_Loop_Exception
...
if <condition>: break
But I am not very happy with this code for 3 reasons
1. Verbosity (i=0 and i++) which doesnt add to the logic
2. The loop now has dual focus. - incrementing i, etc.
3. <most important> A person looks into the code and thinks 'i'
has special significance. His/her mind will be focused on not the
actual reason for the loop.
My first thought would be to simply not use "while True":
INFINITE_LOOP_COUNT = 200
for _ in xrange(INFINITE_LOOP_COUNT):
do_something()
if <condition>: break
else:
raise InfiniteLoopException
The solution that I had in mind is:
while True:
...
if <condition>: break
if inifinte_loop(): raise infiinte_loop_exception
Wherein infinite_loop is a generator, which returns true if i > 200
def infinite_loop():
i = 0
while i < 200:
i++
yield False
yield True
Could somebody let me know whether this is a good option?
To do this, you'd need to do the same sort of thing as you do
with your i/i++ variable:
i = infinite_loop()
while True:
...
if <condition>: break
if i.next(): raise InfiniteLoopException
which doesn't gain much, and makes it a whole lot more confusing.
Could someone chip in with other suggestions?
As an aside: the phrase is "chime in"[1] (to volunteer
suggestions) "Chip in"[2] usually involves contributing money to
a common fund ("care to chip in $10 for Sally's wedding gift from
the office?" where the pool of money would then be used to buy
one large/expensive gift for Sally)
-tkc
[1]
http://www.thefreedictionary.com/chime+in
[2]
http://www.english-test.net/forum/ftopic1768.html
--
http://mail.python.org/mailman/listinfo/python-list
