topic Re: How do I replace missing values in a column using Last Observation Carried Forward (LOCF), or K Nearest Neighbors (without JMP Pro)? in Discussions

How do I replace missing values in a column using Last Observation Carried Forward (LOCF), or K Nearest Neighbors (without JMP Pro)?

WernerL — Fri, 13 Dec 2019 17:16:05 GMT

Hi JMP Community, I have a table with in the first column all days of the year and in the second column a significant number of missing values.

I am looking for a solution to replace in the second column (or create a new 3rd column) the missing values by Last Observation Carried Forward (LOCF)? I cannot seem to find this functionality in JMP?

Alternative, I would like to replace the missing values by K Nearest Neighbors, which I noticed is available for JMP Pro users. Is there a work around for regular JMP users?

Thank you for your help!

Re: How do I replace missing values in a column using Last Observation Carried Forward (LOCF), or K Nearest Neighbors (without JMP Pro)?

txnelson — Fri, 13 Dec 2019 17:43:38 GMT

Attached is a data table with a new column that contains a simple formula that creates your requested Carried Forward value.

Re: How do I replace missing values in a column using Last Observation Carried Forward (LOCF), or K Nearest Neighbors (without JMP Pro)?

jules — Sat, 14 Dec 2019 14:56:13 GMT

Hi @Werner,

I actually prefer a column formula solution like @txnelson suggested because it retains your original data, but in some cases you might find you want to simply fill-in those missing values with the previous value (I do this often when date ranges aren't spanned). If you have JMP 14 or newer, you can use the Replace Missing Values with Previous Values data table right-click function. Select the entire column, then right-click a cell > Fill > Replace Missing with Previous Value.

I hope this helps!

@jules

Re: How do I replace missing values in a column using Last Observation Carried Forward (LOCF), or K Nearest Neighbors (without JMP Pro)?

txnelson — Sat, 14 Dec 2019 15:00:05 GMT

Well, once again I have been shown something new in JMP..... @jules thanks

Re: How do I replace missing values in a column using Last Observation Carried Forward (LOCF), or K Nearest Neighbors (without JMP Pro)?

WernerL — Sat, 14 Dec 2019 15:53:33 GMT

@jules , I agree with you that the solution proposed by @txnelson has the big benefit of maintaining the starting base, hence preferred. Many thanks both for your swift responses! WernerL