How to Get Row Number When There is Missing Data

[#1]

There is missing value in my data.

I'm trying to create script for new column 'Row Number' to get row number of lagged value of Col1(non-missing data).

I'm facing problem when missing data is encountered.

Below is my data with required row number outcome.

How to create script for this?

Row#	Col1	Row Number(outcome)
1	11
2	18	1
3	34	2
4		3
5		3
6		3
7	20	3
8		7
9		7
10	24	7
11	14	10
12	17	11
13		12
14		12
15	16	12
16	25	15

[#2 · Accepted solution]

I think this will do what you're looking for. Lag() without an argument will give the lag of the current column.

New Column( "r",
	Formula(
		If(
			Row() == 1, .,
			Is Missing( Lag( :Col1 ) ), Lag(),
			Row() - 1
		)
	)
)

[#3]

It works.

Thank you.