Srinivas Iyyer wrote:
<snip>
> Coordinates of a variable G1:
> a1 : 3-8
> b2 : 10-25
> c3 : 7-18
> d4 : 10-13
> Now, I have variables G1....Gn. Each variable may
> have individual pieces a1(n),b2(n),c3(n).....z(n).
>
> my kind of solution, which is very crappy (i assume):
>
> Sort the list:
> [3,8] [3,8]
> [10,25] sort [7,18]
> [7,18] --------> [10,13]
> [10,13] [10,25]
>
<snip>
> The question to the forum is, I am using range()
> function to solve this. Since the numbers in the
> example are small, it worked. in the real world
> example , it did not work, because computer slowed
> down and eventually crashed. The range(81393417) is
> really big.
I'm not sure I fully understand the question - do you NEED to loop over
the possible locations, or do you only need to determine the extremes of
the 4 ranges? If you need a loop, xrange is probably the way to go, as
Luke mentions.
If you just need the extremes, you don't need a range(), because it can
be done using zip:
>>> a,b,c,d = [3,8], [10,25], [7,18], [10,13]
>>> candidates = zip(a,b,c,d) # 'merges' the elements of the lists
>>> print candidates # first item contains potential minimums
[(3, 10, 7, 10), (8, 25, 18, 13)] # second item potential maxes
>>> maxrange = [ min(candidates[0]), max(candidates[1]) ]
>>> print maxrange
[3, 25]
Now if you have a non-continuous range, this will still give you the
overlapping area. E.g. if you'd drop c3, it would not affect the result.
If that's a problem, you could loop over the lists directly:
def getMaxRange(locs):
locs.sort() # sorts 'naturally'
#print "sorted locs:", locs
maxrange = locs[0][:] # guaranteed to start with min
for loc in locs[1:]: # loop over rest of locs
if loc[0] <= maxrange[1]:
maxrange[1] = loc[1]
else:
print " discontinuity found for", loc
return None
return maxrange
It's similar to your solution, but without the range - they're superfluous.
Yours,
Andrei
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