What is the most efficient way to search nested lists in python?

Question

I have a list that contains nested lists and I need to know the most efficient way to search within those nested lists.

e.g., if I have

[[\'a\',\'b\         


        

Answer 1

If your arrays are always sorted as you show, so that a[i][j] <= a[i][j+1] and a[i][-1] <= a[i+1][0] (the last element of one array is always less than or equal to the first element in the next array), then you can eliminate a lot of comparisons by doing something like:

a = # your big array

previous = None
for subarray in a:
   # In this case, since the subarrays are sorted, we know it's not in
   # the current subarray, and must be in the previous one
   if a[0] > theValue:
      break
   # Otherwise, we keep track of the last array we looked at
   else:
      previous = subarray

return (theValue in previous) if previous else False

This kind of optimization is only worthwhile if you have a lot of arrays and they all have a lot of elements though.