Column Formula to display difference between two rows of another column

[#1]

My data set is-

Vg Ig Igs
0 1 1
1 5 4
2 7 2
3 3 -4

I would like to create column Igs which is difference between current row and previous row in the column Ig. Is it possible script something like this in jmp.

Thank you

Chivukula

[#2]

Hi:

Perhas this is one way:

[#3]

You can use the LAG function:

New Column( "lgs",
Numeric,
Continuous,
Formula( AsColumn("lg") - Lag( AsColumn("lg"), 1 ) ),
)

[#4 · Accepted solution]

Or this using the DIF function:

New Column( "lgs",
Numeric,
Continuous,
Formula( Dif( :lg, 1 ) )
)

If you are working interactively you can just create a new column and use the formula builder to enter the formula Dif(:lg, 1)

Michael

[#5]

Both the solutions given here work well. I have data that is similar, but in a date format. I want to calculate the difference between rows where the differences are in units such as 'day' or 'year' or 'week' or 'months'. Is there a way to do this?

[#6]

Look into the Scripting Index for the function

     Date Difference()

Help==>Scripting Index

[#7]

Thank you so much for helping.

Regards,
Chivukula

[#8]

Hello:

I am using bivarate plot and adding a fit line. I would like to save slope and intercept values in a text file. I am using following code:

biv=rbiv<Ex1=biv[NumberColBox(13)][2];
show(Ex1);

Show(Ex1) show the value of slope in the log file along with the log of entire session. Is it possible to send JSL command to save the values of just slopes and intercepts in to a new data table or seperate text file from the log.

Thank you

Regards,
Chivukula