How to express the exchange index of the day before and the day after meeting a certain condition?

Represented by ref function. In the communication index, the day before and the day after a certain condition can be represented by the ref function. The ref function can refer to the data before the specified period, and its syntax is: ref(X, n): refer to the data before n days in the x period. For example, to calculate the number of days when the closing price is greater than or equal to the opening price, you can use the following formula: COUNT(CLOSE & gt；; =OPEN, n): Count the days when the closing price is greater than or equal to the opening price within n days.