collections Tricks

collections_tricks.py

from collections import defaultdict, Counter
from typing import Mapping, List

""" Most commom element with Counter.""
stuff: List = ['book', 'book', 'phone', 'book', 'phone']
cnt = Counter(stuff)
# first most common
# first element of the list and a tuple
cnt.most_common(1)[0][0]
# 'book'

"""
Advanced mapping with default dict.
Format:
  {
    key1: {
      key2: {
        x: Hotel,
        y: Counter({key3: n})
      }
    },
  }
"""

data: Mapping = defaultdict(
  lambda: defaultdict(
    lambda: {
      'x': None,
      'y': Counter()
    }
  )
)
elements: List = [some objects]

for el in elements:
    key1 = el.something
    key2 = el.something_else
    key3 = el.something_else_again

    data[key1][key2]['x'] = el.some_value
    # counts occurences
    hotels[key1][key2]['y'].update({key3: 1})