Python - Load Transaction Data Into A List Of Lists, Count Occurrence Of Each String

I'm getting back into python on account of having a homework assignment in it, and am looking for assistance on speeding up sections of my code. My last post was downvoted on accou

Solution 1:

You encountered the sadly classical test on dictionary keys instead of in the dictionary itself.

if item in first_lookup.keys():

should be

if item in first_lookup:

to benefit from dictionary lookup. Explicit call to first_lookup.keys() generates a list in Python 2, so in applies to a list not a dictionary.

In your case, replacing that loop:

forlinein item_data_lol:
    line = line[0]
    foritemin line.split():
        if item in first_lookup.keys():
            first_lookup[item] += 1else:
            first_lookup[item] = 1

by this would speed it up even more (using collections.Counter initialized by a generator comprehension):

importcollectionsfirst_lookup= collections.Counter(item for line in item_data_lol for item in line[0].split())