您可以找到它称为Offset Aliases：
为有用的通用时间序列频率提供了许多字符串别名。我们将这些别名称为偏移别名。
Alias DescriptionB business day frequencyC custom business day frequencyD calendar day frequencyW weekly frequencyM month end frequencySM semi-month end frequency (15th and end of month)BM business month end frequencyCBM custom business month end frequencyMS month start frequencySMS semi-month start frequency (1st and 15th)BMS business month start frequencyCBMS custom business month start frequencyQ quarter end frequencyBQ business quarter end frequencyQS quarter start frequencyBQS business quarter start frequencyA, Y year end frequencyBA, BY business year end frequencyAS, YS year start frequencyBAS, BYS business year start frequencyBH business hour frequencyH hourly frequencyT, min minutely frequencyS secondly frequencyL, ms millisecondsU, us microsecondsN nanoseconds
