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a8dfd403f6
* Add new algorithm index_2d_array_in_1d * Add doctest for iter function * The power of dataclasses * Update index_2d_array_in_1d.py --------- Co-authored-by: Christian Clauss <cclauss@me.com>
106 lines
3.1 KiB
Python
106 lines
3.1 KiB
Python
"""
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Retrieves the value of an 0-indexed 1D index from a 2D array.
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There are two ways to retrieve value(s):
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1. Index2DArrayIterator(matrix) -> Iterator[int]
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This iterator allows you to iterate through a 2D array by passing in the matrix and
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calling next(your_iterator). You can also use the iterator in a loop.
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Examples:
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list(Index2DArrayIterator(matrix))
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set(Index2DArrayIterator(matrix))
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tuple(Index2DArrayIterator(matrix))
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sum(Index2DArrayIterator(matrix))
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-5 in Index2DArrayIterator(matrix)
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2. index_2d_array_in_1d(array: list[int], index: int) -> int
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This function allows you to provide a 2D array and a 0-indexed 1D integer index,
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and retrieves the integer value at that index.
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Python doctests can be run using this command:
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python3 -m doctest -v index_2d_array_in_1d.py
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"""
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from collections.abc import Iterator
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from dataclasses import dataclass
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@dataclass
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class Index2DArrayIterator:
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matrix: list[list[int]]
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def __iter__(self) -> Iterator[int]:
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"""
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>>> tuple(Index2DArrayIterator([[5], [-523], [-1], [34], [0]]))
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(5, -523, -1, 34, 0)
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>>> tuple(Index2DArrayIterator([[5, -523, -1], [34, 0]]))
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(5, -523, -1, 34, 0)
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>>> tuple(Index2DArrayIterator([[5, -523, -1, 34, 0]]))
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(5, -523, -1, 34, 0)
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>>> t = Index2DArrayIterator([[5, 2, 25], [23, 14, 5], [324, -1, 0]])
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>>> tuple(t)
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(5, 2, 25, 23, 14, 5, 324, -1, 0)
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>>> list(t)
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[5, 2, 25, 23, 14, 5, 324, -1, 0]
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>>> sorted(t)
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[-1, 0, 2, 5, 5, 14, 23, 25, 324]
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>>> tuple(t)[3]
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23
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>>> sum(t)
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397
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>>> -1 in t
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True
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>>> t = iter(Index2DArrayIterator([[5], [-523], [-1], [34], [0]]))
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>>> next(t)
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5
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>>> next(t)
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-523
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"""
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for row in self.matrix:
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yield from row
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def index_2d_array_in_1d(array: list[list[int]], index: int) -> int:
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"""
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Retrieves the value of the one-dimensional index from a two-dimensional array.
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Args:
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array: A 2D array of integers where all rows are the same size and all
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columns are the same size.
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index: A 1D index.
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Returns:
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int: The 0-indexed value of the 1D index in the array.
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Examples:
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>>> index_2d_array_in_1d([[0, 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11]], 5)
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5
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>>> index_2d_array_in_1d([[0, 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11]], -1)
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Traceback (most recent call last):
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...
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ValueError: index out of range
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>>> index_2d_array_in_1d([[0, 1, 2, 3], [4, 5, 6, 7], [8, 9, 10, 11]], 12)
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Traceback (most recent call last):
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...
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ValueError: index out of range
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>>> index_2d_array_in_1d([[]], 0)
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Traceback (most recent call last):
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...
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ValueError: no items in array
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"""
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rows = len(array)
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cols = len(array[0])
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if rows == 0 or cols == 0:
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raise ValueError("no items in array")
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if index < 0 or index >= rows * cols:
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raise ValueError("index out of range")
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return array[index // cols][index % cols]
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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