pandas.Series.subtract
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Series.subtract(other, level=None, fill_value=None, axis=0)[source]
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Subtraction of series and other, element-wise (binary operator sub).Equivalent to series - other, but with support to substitute a fill_value for missing data in one of the inputs.Parameters: other : Series or scalar value fill_value : None or float value, default None (NaN) Fill missing (NaN) values with this value. If both Series are missing, the result will be missing level : int or name Broadcast across a level, matching Index values on the passed MultiIndex level Returns: result : Series See also 
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Licensed under the 3-clause BSD License.
    https://pandas.pydata.org/pandas-docs/version/0.20.3/generated/pandas.Series.subtract.html