# Ruby exception occured \`+'
**URL:** https://discuss.elastic.co/t/ruby-exception-occured/90192
**Category:** Logstash
**Created:** [June 21, 2017, 4:07am UTC](https://discuss.elastic.co/t/ruby-exception-occured/90192 "2017-06-21T04:07:16Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Xavier\_Clavien](https://discuss.elastic.co/u/Xavier_Clavien)
#### Post date: [June 21, 2017, 4:07am UTC](https://discuss.elastic.co/t/ruby-exception-occured/90192/1 "2017-06-21T04:07:16Z")
Hi guys
Got strange exception because the result is correct, but then all the code after the one who caused the exception is not working anymore. Here is the code :
> event.set( '[ln\_resistance\_B\_inversion]', ( event.get('[ln\_payload\_decoded]')[72..73] + event.get('[ln\_payload\_decoded]')[70..71] ) )
> event.set( '[ln\_resistance]', [event.get('[ln\_resistance\_B\_inversion]')].pack('H\*').unpack('g').first )
> event.set( '[ln\_temperature\_B\_inversion]', ( event.get('[ln\_payload\_decoded]')[52..53] + event.get('[ln\_payload\_decoded]')[50..51] ) )
> event.set( '[ln\_temperature]', [event.get('[ln\_temperature\_B\_inversion]')].pack('H\*').unpack('g').first )
Then the error that I have is the following :
> exception occurred: undefined method `+' for nil:NilClass
I have the correct value for **ln\_resistance\_B\_inversion** and **ln\_resistance** but not for the others after
Thanks in advanced
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### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [June 21, 2017, 5:33am UTC](https://discuss.elastic.co/t/ruby-exception-occured/90192/2 "2017-06-21T05:33:37Z")
Show an example of an event that results in this error. Use a `stdout { codec => rubydebug }` output.
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 19, 2017, 5:33am UTC](https://discuss.elastic.co/t/ruby-exception-occured/90192/3 "2017-07-19T05:33:44Z")
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