# String Manipulation (Multi Column) fails with NullPointerException

**URL:** <https://forum.knime.com/t/string-manipulation-multi-column-fails-with-nullpointerexception/26498>\
**Category:** KNIME Analytics Platform\
**Tags:** feature-request, bug\
**Created:** [September 3, 2020, 12:41pm UTC](https://forum.knime.com/t/string-manipulation-multi-column-fails-with-nullpointerexception/26498 "2020-09-03T12:41:20Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![mwiegand](https://forum-cdn.knime.com/user_avatar/forum.knime.com/mwiegand/32/66896_2.png) [@mwiegand](https://forum.knime.com/u/mwiegand)\
**Post date:** [September 3, 2020, 12:41pm UTC](https://forum.knime.com/t/string-manipulation-multi-column-fails-with-nullpointerexception/26498/1 "2020-09-03T12:41:20Z")

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Hi there,

in [Column Auto Type Cast Fallback for missing columns](https://forum.knime.com/t/column-auto-type-cast-fallback-for-missing-columns/26497/2) I raised a bug / feature for the Column Auto Type Cast. I recognized that the String Manipulation (Multi Column) throws a NullPointerException error if it encounters a column w/o a specific type.

Henceforth, I’d like to suggest three things:

1. to instate a fallback to skip columns of unknown type OR
2. Just process columns of an unspecific type
3. Enable selection by type like in the column filter node and others

 ![Bildschirmfoto 2020-09-03 um 14.39.35](https://forum-cdn.knime.com/uploads/default/original/3X/a/f/afc42123a27119d025265609580016b129389249.jpeg)

Best  
Mike

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**Author:** ![ipazin](https://forum-cdn.knime.com/user_avatar/forum.knime.com/ipazin/32/806_2.png) [@ipazin](https://forum.knime.com/u/ipazin)\
**Post date:** [September 4, 2020, 8:49am UTC](https://forum.knime.com/t/string-manipulation-multi-column-fails-with-nullpointerexception/26498/2 "2020-09-04T08:49:24Z")

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Hi @mw,

tnx for reporting this. Ticket created to address it. (Internal reference: AP-15075)

Br,  
Ivan

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**Author:** ![mwiegand](https://forum-cdn.knime.com/user_avatar/forum.knime.com/mwiegand/32/66896_2.png) [@mwiegand](https://forum.knime.com/u/mwiegand)\
**Post date:** [September 4, 2020, 9:03am UTC](https://forum.knime.com/t/string-manipulation-multi-column-fails-with-nullpointerexception/26498/3 "2020-09-04T09:03:50Z")

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You are welcome @ipazin. I noticed itÄs the same for the ungroup. Kind of an edge case. Shall I create another ticket?

Btw, this might be caused by the Transpose as this can no determine the column type if it contains no values. Maybe it’s a more wholistic approach to instate a fallback to string type or even be able to determine the fallback manually, though?

![Bildschirmfoto 2020-09-03 um 17.22.48](https://forum-cdn.knime.com/uploads/default/original/3X/3/0/30084c5370edad807a32493f546c112931440046.jpeg)

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**Author:** ![ipazin](https://forum-cdn.knime.com/user_avatar/forum.knime.com/ipazin/32/806_2.png) [@ipazin](https://forum.knime.com/u/ipazin)\
**Post date:** [September 4, 2020, 9:50am UTC](https://forum.knime.com/t/string-manipulation-multi-column-fails-with-nullpointerexception/26498/4 "2020-09-04T09:50:23Z")

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Hi @mw,

Seems so. I’ll add it to existing ticket and then let’s see 🙂

Br,  
Ivan

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**Author:** ![system](https://forum-cdn.knime.com/uploads/default/original/1X/ab3ccf34482a0329361734a18199390177204f15.png) [@system](https://forum.knime.com/u/system)\
**Post date:** [March 5, 2021, 9:50pm UTC](https://forum.knime.com/t/string-manipulation-multi-column-fails-with-nullpointerexception/26498/5 "2021-03-05T21:50:56Z")

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