Hello all,

This is my first query in the RStudio Community, so please tell me if I am doing this wrong.

From this data frame (see subset below), I want to add the "size"(s) of all rows with the same "Row" "Col" identifiers. This is a large data frame, where there are 1536 different "Row" and "Col" positions, with size measurements across 800-1000 time points. More specifically there are 1-32 "Row" identifiers and 1-48 "Col" identifiers, every combinatorial pair resulting in 1536 different combinations.

Ideally, I would like to define a script to loop summing for the different "Row" and "Column" identifiers, and save the output of size sums with the "Row" and "Column" labels in a new csv. I am super green to R, so any pushes in the right direction are appreciated!!

**My Data Frame:**

```
Plate Image_number Row Col size circularity flags Prion
1 1a 129 1 1 110 0.9982 POL32-1856_x129_A1
2 1a 129 1 2 116 0.9598 POL32-1856_x129_A1
3 1a 129 1 3 109 0.8648 SAP1orSMP1-1860or733_xDEL_A1
4 1a 129 1 4 105 0.8955 SAP1orSMP1-1860or733_xDEL_A1
5 1a 129 1 5 100 0.9492 POL32-1856_x129_D1
6 1a 129 1 6 102 0.9682 POL32-1856_x129_D1
>
```

**Hopeful output matrix:**

```
Size_Sum Row Col Prion
1 0 0 0 0
2 0 0 0 0
3 0 0 0 0
4 0 0 0 0
5 0 0 0 0
6 0 0 0 0
...
1536 0 0 0 0
```

I thank you all for your time and consideration