2 DAX
Data Analysis Expressions (DAX) is a formula expression language used in MIcrosoft Analysis Services, Power BI, and Power Pivot in Excel.
DAX overview (MS Docs)
2.1 Row context
DAX is not vectorised like R, nor does it have the concept of a “current row” that you might be familiar with from using VBA or a cursor in procedural or transact SQL. The article Row context in DAX by Marco Russo & Alberto Ferrari (28/03/22) explains this well.