Data science, ringifying & own blocks

[connochaetes]

Hi!

I 'm using "Snap!" for data science. (BTW: Great feature. Thanks!) I 'm trying to build a "select 'columns' from 'table'" block - just for fun. Obviously, there is the "map" block for the same purpose.

(1)

If I ringify the input "columns", it 's working just fine.

(2)

If I do the ringifying in the block definition, I 'm getting an error output.

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Where 's the difference? Is it a bug or is it a feature? Any help would be welcome. If you need to know more details, feel free to ask. Thank you in advance.

[spaceelephant]

The second one first tries to get the second item from the empty slot (false). Because false is not a list, that cannot work. Then it tries to ringify that. The first one first makes a ring for getting the second item of a list and then passes it to map.

[connochaetes]

@spaceelephant Thanks for your immediate help. Now, it seems so obvious.

I was able to achieve my goal by doing it this way:

The input "columns" had to be a reporter.