# Can't do division between two floats
**URL:** https://discuss.elastic.co/t/cant-do-division-between-two-floats/58224
**Category:** Logstash
**Created:** [August 17, 2016, 8:17am UTC](https://discuss.elastic.co/t/cant-do-division-between-two-floats/58224 "2016-08-17T08:17:19Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Fred\_Dionisio](https://discuss.elastic.co/u/Fred_Dionisio)
#### Post date: [August 17, 2016, 8:17am UTC](https://discuss.elastic.co/t/cant-do-division-between-two-floats/58224/1 "2016-08-17T08:17:19Z")
Hello.
This is the code I have.
> mutate {convert =\> ["Average Time of Execution", "float"]}
> mutate {convert =\> ["Average Time of Execution - Last Hour", "float"]}
> ruby {
> code =\> "event['last Hour Perc'] = event['Average Time of Execution'] / event['Average Time of Execution - Last Hour']"
> }
But i'm getting the following error when I execute.
> Ruby exception occurred: undefined method '/' for ...
How do I solve this? Thank you.
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### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [August 17, 2016, 8:22am UTC](https://discuss.elastic.co/t/cant-do-division-between-two-floats/58224/2 "2016-08-17T08:22:12Z")
Please show the full error message. Are you _sure_ the Average Time of Execution field exists for all events?
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### Author:  [@Fred\_Dionisio](https://discuss.elastic.co/u/Fred_Dionisio)
#### Post date: [August 17, 2016, 8:25am UTC](https://discuss.elastic.co/t/cant-do-division-between-two-floats/58224/3 "2016-08-17T08:25:18Z")
Full error:
> Ruby exception occurred: undefined method '/' for [57000.0]: Array {:level=\> error}
> Got this error multiple times and the number 57000 differs. And yes, I've been getting those values without any problem,
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### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [August 17, 2016, 8:46am UTC](https://discuss.elastic.co/t/cant-do-division-between-two-floats/58224/4 "2016-08-17T08:46:43Z")
The problem is that the field is an array and not a singular float value.
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### Author:  [@Fred\_Dionisio](https://discuss.elastic.co/u/Fred_Dionisio)
#### Post date: [August 17, 2016, 8:48am UTC](https://discuss.elastic.co/t/cant-do-division-between-two-floats/58224/5 "2016-08-17T08:48:19Z")
I'm sorry, but how do I access that value?
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### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [August 17, 2016, 8:50am UTC](https://discuss.elastic.co/t/cant-do-division-between-two-floats/58224/6 "2016-08-17T08:50:44Z")
`event['Average Time of Execution'][0]` accesses the first (and in this case only) element of the array. Depending on how it ends up as an array there might be a way to it being an array.
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### Author:  [@Fred\_Dionisio](https://discuss.elastic.co/u/Fred_Dionisio)
#### Post date: [August 17, 2016, 8:59am UTC](https://discuss.elastic.co/t/cant-do-division-between-two-floats/58224/7 "2016-08-17T08:59:37Z")
Totally worked. You're the man 🙂 Cheers
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 4:43am UTC](https://discuss.elastic.co/t/cant-do-division-between-two-floats/58224/8 "2017-07-06T04:43:06Z")