Alteryx Designer Discussions

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Field replaced with nulls in imputation tool--BUG

8 - Asteroid

THe Imputation tool has a bug--if the incoming field has a space (or I assume any special character) the original data are all replaced with null, and a new field with the special character replaced with "_" is created. I'm assuming this is something to do with the transpose tool inside the macro. But i could cause all sorts of problems, and isn't an expected behavior given that one of the user-selected options is whether to output the imputed data as a separate column--if I don't check this, I expect all the data to come out in the original column! If this isn't possible, then I don't think there should be an option, it should just automatically come out in a new column and the old data field should be retained. 


What the output looks like if neither of the extra output field options are selected (where "Data Value" is the original field): 




Alteryx Community Team
Alteryx Community Team



Could you provide the workflow and some false data? Also what version of Alteryx are you on?

Program Manager - Community Platform, Alteryx
8 - Asteroid

It's just the sample data from one of the Alteryx sample workflows. I didn't save the workflow, as I was just messing around to learn about the imputation tool. It happens with any data you enter as long as the field name you select has a space in it, and I've seen the problem documented on other comments/sites, e.g. here


I'm using the most recent version of Alteryx, 2019.3.5

8 - Asteroid

Any word on this?

9 - Comet

I couldn't replicated the error.


Do you have a workflow that produces the issue?

16 - Nebula
16 - Nebula

Hi @alexandramannerings ,


I think the problem is caused by the Cross Tab tool used in the Imputation tool (which is a macro - if you right-click on the Imputation tool, you can select "Open macro: Imputation_v2.yxmc"). The fields selected for imputation are transposed and cross-tabbed, so it happens to these fields. At the end, fields selected for imputation are joined to all other fields and the original field names are restored During this process the "original" field (with space) and the new field (with "_" created by cross tab) seem to be considered as two different fields (the new one contains the data including imputed data, the old one only has  name and type - so it's populated with NULL values). So it's a bug in my opinion and should be fixed.

Currently, you can use a Select tool to remove the additional "old" field with NULL values and rename the field with "_".to it's original name.

Another option is: After adding the Imputation tool to your workflow, right click on the tool and select "Choose tool version" -> "imputation 1", this version does not produce any additional fields.









This issue is resolved in the 2020.2 release available here:


The latest version of the Imputation tool (v3) is used when adding the tool to the canvas in 2020.2.


To update an Imputation tool in an existing workflow, right-click the tool and select Imputation 3.