Want to count up when change occurs in either of two data columns

[#1]

So I have 2 columns of data that have many identical values but which increment at certain points. They are the month and date of data points. Example:

Month	Day	Desired Counter:
1	1	1
1	1	1
2	2	2
2	3	3
3	1	4
3	1	4

Ive tried using lag unsuccessfully as I dont want an increment unless a value changes. I've tried different solutions including:

If(
	Row() == 1, 1,
	Lag( :Month, 1 ) & Lag( :Day, 1 ), Lag( :DesiredCounter, 1 )
)

A similar solution was posted but didnt work for me as I need to keep both columns into account. Can someone help with this? Thank you

[#2]

Here is how I typically do this:

If( Row() == 1,
	x = 1,
	If( Lag( :Month ) != :Month | Lag( :day ) != :Day,
		x = x + 1
	)
);
x;

[#3]

Hey Jim,

Thanks for your reply. So I tried this and I'm just getting a bunch of 1's still. Is there anything else I might need to add? X is our desired counting column right? Thank you

[#4 · Accepted solution]

Here is a script that creates your sample data table, and applies the formula to the Desired Counter: column

New Table( "Example",
	Add Rows( 6 ),
	New Column( "Month",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Set Values( [1, 1, 2, 2, 3, 3] )
	),
	New Column( "Day",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Set Values( [1, 1, 2, 3, 1, 1] )
	),
	New Column( "Desired Counter:",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Formula(
			If( Row() == 1,
				x = 1,
				If( Lag( :Month ) != :Month | Lag( :Day ) != :Day,
					x = x + 1
				)
			);
			x;
		)
	)
)

It produces this data table:

[#5]

Oh, Im sorry, I thought I had to sub a column in for x. Nevermind, it works, thank you!!!