# Logstash to convert scientific notation to float
**URL:** https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231
**Category:** Logstash
**Created:** [October 10, 2022, 1:46pm UTC](https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231 "2022-10-10T13:46:58Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@the\_elkguy](https://discuss.elastic.co/u/the_elkguy)
#### Post date: [October 10, 2022, 1:46pm UTC](https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231/1 "2022-10-10T13:46:58Z")
Hello,
I'm using logstash ruby filter to convert scientific notation from string to float which seem to be not working. I have used GROK to extract the scientific notation (1.989e-04) from the message and now converting to real number (0.0001989).
**The values i get is just 0**
Here is my code.
```auto
ruby {
code => "
require 'bigdecimal'
event.set('sourceOffset', ('%.20f' % (BigDecimal.new event.get('sourceOffset'))).sub(/\.?0*$/, '').to_f)
"
```
Also the **logstash error:**
[2022-10-10T09:09:08,123][ERROR][logstash.filters.ruby] Ruby exception occurred: invalid value for BigDecimal(): "-" {:class=\>"ArgumentError", :backtrace=\>["org/jruby/ext/bigdecimal/RubyBigDecimal.java:716:in `new'", "(ruby filter code):4:in `block in filter\_method'", "/apps/elk/logstash-7.17.1/vendor/bundle/jruby/2.5.0/gems/logstash-filter-ruby-3.1.8/lib/logstash/filters/ruby.rb:96:in `inline_script'", "logstash-7.17.1/vendor/bundle/jruby/2.5.0/gems/logstash-filter-ruby-3.1.8/lib/logstash/filters/ruby.rb:89:in `filter'", "logstash-7.17.1/logstash-core/lib/logstash/filters/base.rb:159:in `do_filter'", "logstash-7.17.1/logstash-core/lib/logstash/filters/base.rb:178:in `block in multi\_filter'", "org/jruby/RubyArray.java:1821:in `each'", "logstash-7.17.1/logstash-core/lib/logstash/filters/base.rb:175:in `multi\_filter'", "org/logstash/config/ir/compiler/AbstractFilterDelegatorExt.java:134:in `multi_filter'", "/logstash-7.17.1/logstash-core/lib/logstash/java_pipeline.rb:299:in `block in start\_workers'"]}
Appreciate some help.
thanks,
---
### Author:  [@Badger](https://discuss.elastic.co/u/Badger)
#### Post date: [October 10, 2022, 4:34pm UTC](https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231/2 "2022-10-10T16:34:48Z")
If your [sourceOffset] field contains "1.989e-04" then your ruby filter will produce
```
"sourceOffset" => 0.0001989,
```
However, you have no exception handling. The `Ruby exception occurred: invalid value for BigDecimal(): "-"` occurs if the [sourceOffset] field contains `-`.
You could use try/catch or test whether [sourceOffset] is in scientific notation using a [regexp](https://stackoverflow.com/questions/50528957/regex-to-match-scientific-notation-of-numbers-but-not-other-letters).
---
### Author:  [@Rios](https://discuss.elastic.co/u/Rios)
#### Post date: [October 10, 2022, 4:45pm UTC](https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231/3 "2022-10-10T16:45:24Z")
Have you tried with mutate convert?
```auto
mutate {
convert => {
"sourceOffset" => "float"
}
}
```
---
### Author:  [@the\_elkguy](https://discuss.elastic.co/u/the_elkguy)
#### Post date: [October 17, 2022, 2:58pm UTC](https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231/4 "2022-10-17T14:58:52Z")
@Badger
Yes that's working. I had to change to GROK patterns as %{USERNAME:sourceoffset}
then i ran the Ruby without the (.to\_f) which worked.
the values are now coming as String.
Ruby failed to convert that to Float and so many error;s about the exceptions.
@Rios
I also treid to convert that to float, that actually shows back the scientific notation value again. so i removed that.
The only issue now is how do I convert it to Number type.
---
### Author:  [@Rios](https://discuss.elastic.co/u/Rios)
#### Post date: [October 17, 2022, 3:04pm UTC](https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231/5 "2022-10-17T15:04:07Z")
Number as integer or number as type?
If is as the type, it's already, and you have recreate mappings in Kibana.
---
### Author:  [@the\_elkguy](https://discuss.elastic.co/u/the_elkguy)
#### Post date: [October 17, 2022, 3:54pm UTC](https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231/6 "2022-10-17T15:54:17Z")
@Rios
Apparently its not
Ruby is converting as String.
---
### Author:  [@Rios](https://discuss.elastic.co/u/Rios)
#### Post date: [October 17, 2022, 4:01pm UTC](https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231/7 "2022-10-17T16:01:36Z")
When is converted to integer or float it's number. Use debug, will see values.
---
### Author:  [@the\_elkguy](https://discuss.elastic.co/u/the_elkguy)
#### Post date: [October 19, 2022, 9:25am UTC](https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231/8 "2022-10-19T09:25:54Z")
My ruby is converting the scientific notation in string but i need in float
i need help here,
Mutate filter convert is showing back the scientific notation in number type # ( -1.038e-06 ) but not in decimal -0.000001038.
```auto
ruby {
code => "
require 'bigdecimal'
event.set('chronyoffset', ('%.20f' % (BigDecimal.new event.get('chronyoffset'))).sub(/\.?0*$/, ''))
"
}
```
Please provide me correct ruby code to fix this.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [November 16, 2022, 9:26am UTC](https://discuss.elastic.co/t/logstash-to-convert-scientific-notation-to-float/316231/9 "2022-11-16T09:26:26Z")
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