Python defaultdict examples

python-defaultdict-examples.py

# SOME_SENTENCE = input("Enter a sentence: ")
from collections import defaultdict
from collections.abc import Iterable

SOME_SENTENCE = (
    "The cat sat on the mat, "
    "and the cat played with the mat "
    "while the cat watched the sun."
)

SOME_NAMES = [
    "Alice",
    "Bob",
    "Bob",
    "Bob",
    "Sam",
    "Sam",
    "Charlie",
    "Jessica",
    "Jessica",
    "Diana",
    "Fiona",
    "George",
    "Nick",
    "Jo",
    "Jo",
    "Isaac",
    "Julia",
]


SOME_PLACES_WITH_PEOPLE = {
    "The Red Square": {"Ivan", "Olga", "Peter", "Sergey"},
    "The Big Ben": {"Kate", "Ivan", "Charles", "Olga"},
    "The Golden Bridge": {"John", "Ivan", "Kate", "Peter"},
}

# SOME_PLACES_WITH_PEOPLE = {
#     "Ivan": [
#         "The Red Square",
#         "The Big Ben",
#         "The Golden Bridge",
#     ],
#     "Kate": [
#         "The Big Ben",
#         "The Golden Bridge",
#     ],
# }


def demo_count_words_in_sentence(sentence: str) -> None:
    words = (
        # original
        sentence
        # lower case
        .lower()
        # remove dots
        .replace(".", "")
        # remove commas
        .replace(",", "")
        # split by space
        .split()
    )
    print(words)
    words_counts: defaultdict[str, int] = defaultdict(int)
    # print(words_counts)
    # print("foobar count:", words_counts["foobar"])
    # print(words_counts)
    # print("foobar count:", words_counts["foobar"])
    # words_counts["foobar"] = 42
    # print("foobar count:", words_counts["foobar"])
    # print(words_counts)
    for word in words:
        words_counts[word] += 1
        # if word not in words_counts:
        #     words_counts[word] = 0
        # words_counts[word] += 1
        # if word in words_counts:
        #     words_counts[word] += 1
        # else:
        #     words_counts[word] = 1

    print(words_counts)


def demo_group_names_by_length(all_names: Iterable[str]) -> None:
    # names_by_length: defaultdict[int, list[str]] = defaultdict(list)
    names_by_length: defaultdict[int, set[str]] = defaultdict(set)
    for name in all_names:
        names_by_length[len(name)].add(name)

    for count, names in sorted(names_by_length.items(), reverse=True):
        print("===", count)
        print(names)


def demo_may_seen_each_other(
    places_with_people: dict[str, set[str]],
) -> None:
    # {"John": {"Venue A": {"A", "B", "C"}}}
    type PlacesWithPeople = defaultdict[str, defaultdict[str, set[str]]]
    places_where_seen_each_other: PlacesWithPeople = (
        # defaultdict(lambda: defaultdict(lambda: {"Airport"}))
        defaultdict(lambda: defaultdict(set))
    )
    for venue, people in places_with_people.items():
        for person1 in people:
            for person2 in people:
                if person1 != person2:
                    places_where_seen_each_other[person1][venue].add(person2)

    print(places_where_seen_each_other)

    seen = (
        "Olga"
        in places_where_seen_each_other["Ivan"]["The Red Square"]
        # places_where_seen_each_other["Ivan"]["The Red Square"].__contains__("Olga")
    )
    print("Ivan seen Olga at The Red Square:", seen)

    seen = "Kate" in places_where_seen_each_other["Charles"]["The Big Ben"]
    print("Charles seen Kate at The Big Ben:", seen)

    seen = "Kate" in places_where_seen_each_other["Charles"]["The Golden Bridge"]
    print("Charles seen Kate at The Golden Bridge:", seen)


def main() -> None:
    demo_count_words_in_sentence(SOME_SENTENCE)
    demo_group_names_by_length(SOME_NAMES)
    demo_may_seen_each_other(SOME_PLACES_WITH_PEOPLE)


if __name__ == "__main__":
    main()