# Math & date: ruby & logstash
**URL:** https://discuss.elastic.co/t/math-date-ruby-logstash/45945
**Category:** Logstash
**Created:** [March 31, 2016, 1:33pm UTC](https://discuss.elastic.co/t/math-date-ruby-logstash/45945 "2016-03-31T13:33:11Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@garanews](https://discuss.elastic.co/u/garanews)
#### Post date: [March 31, 2016, 1:33pm UTC](https://discuss.elastic.co/t/math-date-ruby-logstash/45945/1 "2016-03-31T13:33:11Z")
Hello,
I have some log files that have rows like this:
station1 on 15387 15646 130 Y
Values are separated by tab
With logstash I would transform the first\_seen and last\_seen in timestamp, because they are the number of days after 1/1/1970
So basically I should just multiply by 86400 to have seconds and then use the logstash date funcion.
The code below is not doing what I am expecting
```
if [type] == "test_log" {
csv {
separator => " "
columns => ["client", "status", "first_seen", "last_seen", "times_seen", valid"]
}
```
if [first\_seen] != "-" {
ruby
{ code =\> "event['first\_seen'] = event['first\_seen'].to\_f \* 86400"}
date {
match =\> ["first\_seen", "UNIX"]
}
}
if [ast\_seen] != "-" {
ruby
{ code =\> "event['last\_seen'] = event['last\_seen'].to\_f \* 86400"}
date {
match =\> ["last\_seen", "UNIX"]
}
}
It seems that out of ruby code the variable is not set and in the logstash.log I have errors like "the - is not valid unix time" repeated for milion of times.
Can you please give me an hint?
Thanks in advance
---
### Author:  [@kirill\_polishchuk](https://discuss.elastic.co/u/kirill_polishchuk)
#### Post date: [March 31, 2016, 5:09pm UTC](https://discuss.elastic.co/t/math-date-ruby-logstash/45945/2 "2016-03-31T17:09:35Z")
You should try convert to integer, instead of to float:
ruby
{ code =\> "event['last\_seen'] = event['last\_seen'].to\_i\* 86400"}
when float you are getting epoch date like: `1329436800.0` ( epoch date with comma - is not well formatted date)
---
### Author:  [@garanews](https://discuss.elastic.co/u/garanews)
#### Post date: [April 1, 2016, 10:28am UTC](https://discuss.elastic.co/t/math-date-ruby-logstash/45945/3 "2016-04-01T10:28:03Z")
I did but nothing changed...
---
### Author:  [@garanews](https://discuss.elastic.co/u/garanews)
#### Post date: [April 8, 2016, 7:05am UTC](https://discuss.elastic.co/t/math-date-ruby-logstash/45945/4 "2016-04-08T07:05:00Z")
any other suggestion?
Thanks
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 5:03am UTC](https://discuss.elastic.co/t/math-date-ruby-logstash/45945/5 "2017-07-06T05:03:09Z")