Replace re.split with regular split to get the same result (you can use the json library and the loads function) The code: f = open('purchase_log.txt', encoding='utf-8') import re purchases = {} for i, line in enumerate(f): line = re.split(r",|:", line.strip()) keys = line[1] values = line[3] purchases[keys] = values

import json
def normal_split(data):
  return data.split(',')

purchases = {}
for i, line in enumerate(f):
    line = json.loads(line.strip())
    keys = line['user_id']
    values = line['category']
    purchases[keys] = values