How to handle a loop end of column list loop

Hi everybody!

I have created a Column List Loop Start to deal with each column data.
At the end of the loop, the result of each loop need to be concatenated ( like to concatenate all columns to one column).
I cannot find how to handle the end of the loop, how to concatenate column of every loop into one column. Is it need to be write to a csv file in every loop?

If detail information is needed, please reply me and I will upload my data and current workflow tomorrow then.

Thank you!

I don’t understand exactly what you mean; but it seems to me that the simple “Loop End” node is what you are looking for. It concatenates the result of every loop iteration to the bottom of the results table. Alternatively, the “Loop End (column append)” node appends the result of every loop iteration to the results table as a new column.

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You have to change column names or even resort the columns in a way that all iterations have the same output table structure. Then you can use the Loop End node (even without checking the “Allow changing table specifications” option) to concatenate the outputs.

Here you can read more about loops:



Thanks for your reply. I just tried the “Loop End (column append)” node and it seemed worked!.

Thank you for replied.

I tried Loop End node yesterday, and got an error of “Execute failed: Input table’s structure differs from reference (first iteration) table: different column counts 3 vs. 4”.

I don’t understand the error because I think all iterations output table should have same structure in my workflow. I will read the the link information which you have shared, try to find the reason.

But anyway, after I checked the “Allow changing table specifications” option, the workflow has already worked! Appreciate for your information!


Hi there!

In order to check what happens in loop there is option Step Loop Execution. Pretty handy when error pops out :wink:



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That’s it ! I think I can figure out the error by this, thanks again!

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I met a very similar loop end problem. Have created a new topic.
Thanks all again.

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