Write me an excel function to sum up the values in the cells in a column to the left if the cell is full
 Assuming that the column to the left is column A and you want to sum up the values from A1 to the last cell with a value in column A, you can use the following Excel function:
```less
=SUM(A1:A$1)
```
Place this function in the cell where you want the sum to appear, and then drag it down to copy it to the other cells in the column to the right of column A. The dollar sign in the reference to cell A$1 will keep that row number fixed as you copy the function to other cells, so that it always refers to the same cell in column A.

Excel will automatically adjust the range of cells being summed as you copy the function to other cells, so that it always includes all the cells in column A to the left of the current cell. For example, if you place the function in cell B1, it will sum the values in cells A1 to A1, giving you the value in cell A1. If you place the function in cell B2, it will sum the values in cells A1 to A2, giving you the sum of the first two cells in column A. And so on.

Note that this function assumes that there are no empty cells in the range you are summing. If there are empty cells, you can use the following function instead:
```swift
=SUM(A
=SUMIF(LEFT(A1:A1000),"*",B1:B1000)