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799fde4c07
* Update linear_search.py Python implementation of recursive linear search algorithm * Update linear_search.py Added different doctests Added the parameter hints Handled the exception * Update linear_search.py added parameter hints to linear_search * Update linear_search.py Both the functions return the index if the target is found and -1 if it is not found The rec_linear_search raises an exception if there is an indexing problem Made changes in the doc comments * Update linear_search.py Co-authored-by: Christian Clauss <cclauss@me.com>
78 lines
2.3 KiB
Python
78 lines
2.3 KiB
Python
"""
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This is pure Python implementation of linear search algorithm
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For doctests run following command:
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python3 -m doctest -v linear_search.py
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For manual testing run:
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python3 linear_search.py
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"""
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def linear_search(sequence: list, target: int) -> int:
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"""A pure Python implementation of a linear search algorithm
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:param sequence: a collection with comparable items (as sorted items not required
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in Linear Search)
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:param target: item value to search
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:return: index of found item or None if item is not found
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Examples:
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>>> linear_search([0, 5, 7, 10, 15], 0)
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0
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>>> linear_search([0, 5, 7, 10, 15], 15)
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4
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>>> linear_search([0, 5, 7, 10, 15], 5)
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1
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>>> linear_search([0, 5, 7, 10, 15], 6)
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-1
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"""
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for index, item in enumerate(sequence):
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if item == target:
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return index
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return -1
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def rec_linear_search(sequence: list, low: int, high: int, target: int) -> int:
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"""
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A pure Python implementation of a recursive linear search algorithm
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:param sequence: a collection with comparable items (as sorted items not required
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in Linear Search)
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:param low: Lower bound of the array
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:param high: Higher bound of the array
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:param target: The element to be found
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:return: Index of the key or -1 if key not found
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Examples:
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>>> rec_linear_search([0, 30, 500, 100, 700], 0, 4, 0)
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0
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>>> rec_linear_search([0, 30, 500, 100, 700], 0, 4, 700)
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4
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>>> rec_linear_search([0, 30, 500, 100, 700], 0, 4, 30)
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1
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>>> rec_linear_search([0, 30, 500, 100, 700], 0, 4, -6)
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-1
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"""
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if not (0 <= high < len(sequence) and 0 <= low < len(sequence)):
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raise Exception("Invalid upper or lower bound!")
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if high < low:
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return -1
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if sequence[low] == target:
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return low
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if sequence[high] == target:
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return high
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return rec_linear_search(sequence, low + 1, high - 1, target)
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if __name__ == "__main__":
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user_input = input("Enter numbers separated by comma:\n").strip()
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sequence = [int(item.strip()) for item in user_input.split(",")]
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target = int(input("Enter a single number to be found in the list:\n").strip())
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result = linear_search(sequence, target)
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if result != -1:
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print(f"linear_search({sequence}, {target}) = {result}")
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else:
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print(f"{target} was not found in {sequence}")
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