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recursive list python

The Amateur answered on December 21, 2022 Popularity 6/10 Helpfulness 1/10

answer recursive list python

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recursive list python

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class RecursiveList:
    """A recursive implementation of a List

    Representation Invariants:
        - (self._first is None) == (self._rest is None)
    """
    _first  # The first item in this list, or None if this list is empty.
    _rest:  # A list containing the items in this list that come after the first one, or None if this list is empty.

    def __init__(self, first, rest) -> None:
        """Initialize a new recursive list."""
        self._first = first
        self._rest = rest

    def is_empty(self) -> bool:
        """Return whether this list is empty.
        """
        return self._first is None

    def sum(self) -> int:
        """Return the sum of the elements in this list.
        """
        if self._first is None:  # Base case: this list is empty
            return 0
        else:
            return self._first + self._rest.sum()
	
    def to_list(self) -> list:
        """Return a Python list containing the items stored in this list.
        """
        if self.is_empty():
            return []
        elif self._rest is None:
            return self._first
        else:
            return [self._first] + self._rest.to_list()

    def __contains__(self, item) -> bool:
        """Return whether the given item is in this list.
        """
        if self.is_empty():
            return False
        elif self._rest is None:
        	return self._first == item
        else:
        	return item in self._rest or item == self._first

    def index(self, item) -> int:
        """Return the index of the first occurrence of the given item in this list.
        """
        if self.is_empty():
            raise ValueError
        elif self._first == item:
            return 0
        else:
            return 1 + self._rest.index(item)

    def insert(self, i: int, item) -> None:
        """Insert the given item in to this list at index i
        """
        if self.is_empty() and i > 0:
            raise IndexError
        elif i == 0:
            self._rest = RecursiveList(self._first, self._rest)
            self._first = item
        else:
            self._rest.insert(i - 1, item)

Popularity 6/10 Helpfulness 1/10 Language python

Source: Grepper

Tags: list python

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Contributed on Feb 02 2023

The Amateur

0 Answers Avg Quality 2/10

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create list recursively python

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def rec(S):
    if len(S) == 1:
        return S
    return S[-1] + rec(S[:-1])

Popularity 6/10 Helpfulness 2/10 Language python

Source: www.codingninjas.com

Tags: python list

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Contributed on Dec 21 2022

Prickly Pigeon

0 Answers Avg Quality 2/10

recursive list python

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