love_gannon.py 文件源码

def quiet_days(series,
               n_days=5,
               period='min'):
    """
    Given a pandas time series *series*, return a mapping between
    months and the *n_days* quietest days for that month. See (4) of
    Love and Gannon. The parameter *period* gives the sampling period
    (`'min'` = 1 measurement per minute).
    """
    quiet_day_map = {}
    delta_H_i = series.diff().abs().\
                groupby(PD.TimeGrouper(freq='D')).\
                filter(lambda x: x.isnull().sum() <= int(0.5 * SAMPLES[period])).\
                groupby(PD.TimeGrouper(freq='D')).mean()
    for month, delta_H_i_month in delta_H_i.groupby(PD.TimeGrouper(freq='M')):
        quiet_day_map[month] = delta_H_i_month.nsmallest(n_days).sort_index().index
    return quiet_day_map