How can a new column be altered according to a specific time period?

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To alter a new column according to a specific time period, you can use a conditional statement or a function that checks the time period and assigns a value to the new column accordingly.

For example, if you have a column of dates and you want to create a new column that indicates whether the date is in the current year or not, you can use the following formula in Excel:

=IF(YEAR(A2)=YEAR(TODAY()), "Current Year", "Not Current Year")

This formula checks if the year of the date in cell A2 is the same as the current year (determined by the TODAY() function), and if it is, it assigns the value "Current Year" to the new column. If not, it assigns "Not Current Year".

Similarly, if you have data that spans multiple time periods (e.g. years, months, days) and you want to group them together and create a new column based on those groups, you can use the GROUPBY function in SQL or a similar function in other programming languages. The GROUPBY function groups the data by a specific column (such as date) and then allows you to apply a function to those groups to create a new column.