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I'm going to have 1 small dictionary (between 5 and 20 keys) that will be referenced up to a hundred times or so for one page load in python 2.5.
I'm starting to name the keys which it will be looking up and I was wondering if there is a key naming convention I could follow to help dict lookup times.
836
Lookups are faster in dictionaries because Python implements them using hash tables. If we explain the difference by Big O concepts, dictionaries have constant time complexity, O(1) while lists have linear time complexity, O(n).
It is more efficient to use dictionaries for the lookup of elements as it is faster than a list and takes less time to traverse. Moreover, lists keep the order of the elements while dictionary does not. So, it is wise to use a list data structure when you are concerned with the order of the data elements.
Compared with lists and tuples, the performance of dictionaries is better, especially for search, add, and delete operations. A dictionary can be completed within a constant time complexity.
Second, a dictionary key must be of a type that is immutable. For example, you can use an integer, float, string, or Boolean as a dictionary key. However, neither a list nor another dictionary can serve as a dictionary key, because lists and dictionaries are mutable.
I had to test ;-)
using
1
"one"
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
as one of the keys into a dictionary of length 4. Iterating 10,000,000 times and measuring the times. I get this result:
<function f1 at 0xb779187c>
f1 3.64
<function f2 at 0xb7791bfc>
f2 3.48
<function f3 at 0xb7791bc4>
f3 3.65
I.e no difference...
My code
117
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