Rowwwise operations are a quite frequent operations in data analysis. The R language environment is particularly strong in column wise operations. This is due to technical reasons, as data frames are internally built as column-by-column structures, hence column wise operations are simple, rowwise more difficult.
This post looks at some rather general way to comput rowwise statistics. Of course, numerous ways exist and there are quite a few tutorials around, notably by Jenny Bryant, and by Emil Hvitfeldt to name a few.
The ideal solution is to have your data be properly columnar, but if you’re in a pinch, it’s good to know that you can do this.