topic Re: Need help for using Lag function in Discussions

Need help for using Lag function

switzal87 — Mon, 06 Nov 2017 08:49:33 GMT

Hello everyone!

Hope someone could help me with this:

What is is the expected output of the following code?

After evaluation I get the following Log:

And the new columns just looks like this:

SliderID column is :

Hope someone could enlighten me with this! thanks in advance! :)

Re: Need help for using Lag function

stephen_pearson — Tue, 07 Nov 2017 21:30:55 GMT

Your formula is missing an if statement. It should be something like

Formula(If(:sliderID == lag(:sliderID,1),1,0))

I would recommend you get all the steps working by using the menus and mouse clicks before trying to script it.

Re: Need help for using Lag function

txnelson — Tue, 07 Nov 2017 21:34:33 GMT

Your formula

     :SliderID == Lag(:SiiderID, 1 )

is a boolean operation. When the current rows value of SliderID is equal to the previous row's value os SliderID, "Lag(:SliderID, 1)", the value of the comparison will be "True" and therefore it will return a numeric value of 1. If the comparison of the current row's value of SliderID is not equal to the previous row's value of SliderID, the returned value will be a 0.

@stephen_pearson modification of turning the formula into an "If" clause will result in the same values.

The error that is listed out, is a response to the line

     dABCR << Delete Rows;

and it is being returned, because no rows had been selected as a result of the line

     dABCR << Select Where(SN == 1);

The only correction to this line would be to scope the column reference by placing a ":" in front of SN

     dABCR << Select Where(:SN==1);

Re: Need help for using Lag function

Craige_Hales — Tue, 07 Nov 2017 21:35:09 GMT

Looking at the data, I don't see any repeated SliderID values, so it might be working correctly. You might use

try(dABCE<<DeleteRows)

to catch and ignore the error when there is nothing to delete.

edit: well, not try, if it isn't throwing an error. Maybe this.

Re: Need help for using Lag function

switzal87 — Wed, 15 Nov 2017 07:54:42 GMT

this worked for me! thanks a lot! :)

Re: Need help for using Lag function

switzal87 — Wed, 15 Nov 2017 07:56:49 GMT

that was enlightening! appreciated the brief explanation on how the formula works! :)