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1e64bf4600
* added harmonic mean * Update maths/series/harmonic_mean.py Updated the write-up of reference given in the code. Co-authored-by: John Law <johnlaw.po@gmail.com> * changes in arithmetic and geometric mean code * mean and series added in a single file Co-authored-by: John Law <johnlaw.po@gmail.com>
93 lines
2.7 KiB
Python
93 lines
2.7 KiB
Python
"""
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Harmonic mean
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Reference: https://en.wikipedia.org/wiki/Harmonic_mean
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Harmonic series
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Reference: https://en.wikipedia.org/wiki/Harmonic_series(mathematics)
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"""
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def is_harmonic_series(series: list) -> bool:
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"""
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checking whether the input series is arithmetic series or not
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>>> is_harmonic_series([ 1, 2/3, 1/2, 2/5, 1/3])
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True
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>>> is_harmonic_series([ 1, 2/3, 2/5, 1/3])
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False
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>>> is_harmonic_series([1, 2, 3])
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False
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>>> is_harmonic_series([1/2, 1/3, 1/4])
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True
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>>> is_harmonic_series([2/5, 2/10, 2/15, 2/20, 2/25])
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True
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>>> is_harmonic_series(4)
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Traceback (most recent call last):
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...
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ValueError: Input series is not valid, valid series - [1, 2/3, 2]
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>>> is_harmonic_series([])
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Traceback (most recent call last):
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...
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ValueError: Input list must be a non empty list
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>>> is_harmonic_series([0])
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Traceback (most recent call last):
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...
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ValueError: Input series cannot have 0 as an element
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>>> is_harmonic_series([1,2,0,6])
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Traceback (most recent call last):
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...
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ValueError: Input series cannot have 0 as an element
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"""
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if not isinstance(series, list):
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raise ValueError("Input series is not valid, valid series - [1, 2/3, 2]")
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if len(series) == 0:
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raise ValueError("Input list must be a non empty list")
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if len(series) == 1 and series[0] != 0:
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return True
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rec_series = []
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series_len = len(series)
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for i in range(0, series_len):
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if series[i] == 0:
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raise ValueError("Input series cannot have 0 as an element")
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rec_series.append(1 / series[i])
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common_diff = rec_series[1] - rec_series[0]
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for index in range(2, series_len):
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if rec_series[index] - rec_series[index - 1] != common_diff:
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return False
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return True
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def harmonic_mean(series: list) -> float:
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"""
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return the harmonic mean of series
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>>> harmonic_mean([1, 4, 4])
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2.0
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>>> harmonic_mean([3, 6, 9, 12])
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5.759999999999999
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>>> harmonic_mean(4)
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Traceback (most recent call last):
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...
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ValueError: Input series is not valid, valid series - [2, 4, 6]
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>>> harmonic_mean([1, 2, 3])
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1.6363636363636365
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>>> harmonic_mean([])
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Traceback (most recent call last):
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...
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ValueError: Input list must be a non empty list
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"""
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if not isinstance(series, list):
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raise ValueError("Input series is not valid, valid series - [2, 4, 6]")
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if len(series) == 0:
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raise ValueError("Input list must be a non empty list")
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answer = 0
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for val in series:
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answer += 1 / val
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return len(series) / answer
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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