【读代码】关于日期的处理

return np.vstack([feat(dates) for feat in time_features_from_frequency_str(freq)])

很多的类，用字典，调用类，还有类的重命名

除以 23 表示第几个小时，一天中的第几个小时

dayofhour是读出来的

dayofweek 是 python 内置库转换来

dayofmonth 也是可以直接读出来的

dayof year 也是直接读出来

为什么都减去 0.5：中心化

 奥，所以除以的数都比正常的小 1

规律：

为什么这里除以  11

class MonthOfYear(TimeFeature):

"""Month of year encoded as value between [-0.5, 0.5]"""

def __call__(self, index: pd.DatetimeIndex) -> np.ndarray:

return (index.month - 1) / 11.0 - 0.5

这里的对于日期的编码还蛮有趣

class DayOfWeek(TimeFeature):
    """Hour of day encoded as value between [-0.5, 0.5]"""

    def __call__(self, index: pd.DatetimeIndex) -> np.ndarray:
        return index.dayofweek / 6.0 - 0.5 # Python内部返回 0——6 python内部计算 day 是周几，同时 除以 6 是为了把 周一到周六调成 0——1的范围，周一默认 0，周二=1，周日=6 so__都可以调到 0——1的范围内


class DayOfMonth(TimeFeature):
    """Day of month encoded as value between [-0.5, 0.5]"""

    def __call__(self, index: pd.DatetimeIndex) -> np.ndarray:
        return (index.day - 1) / 30.0 - 0.5 # 1——31


class DayOfYear(TimeFeature):
    """Day of year encoded as value between [-0.5, 0.5]"""

    def __call__(self, index: pd.DatetimeIndex) -> np.ndarray:
        return (index.dayofyear - 1) / 365.0 - 0.5 # 1——366


class MonthOfYear(TimeFeature):
    """Month of year encoded as value between [-0.5, 0.5]"""

    def __call__(self, index: pd.DatetimeIndex) -> np.ndarray:
        return (index.month - 1) / 11.0 - 0.5 # 1——12


class WeekOfYear(TimeFeature):
    """Week of year encoded as value between [-0.5, 0.5]"""

    def __call__(self, index: pd.DatetimeIndex) -> np.ndarray:
        return (index.isocalendar().week - 1) / 52.0 - 0.5 # 返回 1——53，--》-1 到 0——52 》-0.5 中心化