# How to convert a list of string to a list of date in filter?
**URL:** https://discuss.elastic.co/t/how-to-convert-a-list-of-string-to-a-list-of-date-in-filter/47886
**Category:** Logstash
**Created:** [April 20, 2016, 9:37am UTC](https://discuss.elastic.co/t/how-to-convert-a-list-of-string-to-a-list-of-date-in-filter/47886 "2016-04-20T09:37:50Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Morriaty](https://discuss.elastic.co/u/Morriaty)
#### Post date: [April 20, 2016, 9:37am UTC](https://discuss.elastic.co/t/how-to-convert-a-list-of-string-to-a-list-of-date-in-filter/47886/1 "2016-04-20T09:37:50Z")
The input had a field named `valid_dates` which is a string column from mysql(jdbc).It formatted like this
```auto
"2014-09-10 00:00:00,2014-08-21 17:02:02,2014-06-19 00:00:00,2014-08-20 14:29:09"
```
And the filter was
```json
filter {
mutate => {
split => { "valid_dates" => "," }
}
ruby {
code => "require 'date'
# I also tried this, failed too.
# event['valid_dates']=event['valid_dates'].split(",")
event['valid_dates']=event['valid_dates'].map {|dt| Datetime.strptime(dt,'%Y-%m-%d %H:%M:%S')}"
}
}
```
The error was
```auto
Ruby exception occurred: uninitialized constant LogStash::Filters::Ruby::Datetime {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
Ruby exception occurred: uninitialized constant LogStash::Filters::Ruby::Datetime {:level=>:error}
Ruby exception occurred: uninitialized constant LogStash::Filters::Ruby::Datetime {:level=>:error}
Ruby exception occurred: uninitialized constant LogStash::Filters::Ruby::Datetime {:level=>:error}
Ruby exception occurred: uninitialized constant LogStash::Filters::Ruby::Datetime {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
```
BTW, I wanna know if logstash filter could support python or some other script languages.
---
### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [April 20, 2016, 9:47am UTC](https://discuss.elastic.co/t/how-to-convert-a-list-of-string-to-a-list-of-date-in-filter/47886/2 "2016-04-20T09:47:36Z")
I believe the class is named DateTime, not Datetime.
> BTW, I wanna know if logstash filter could support python or some other script languages.
I don't think that's very likely.
---
### Author:  [@Morriaty](https://discuss.elastic.co/u/Morriaty)
#### Post date: [April 20, 2016, 10:47am UTC](https://discuss.elastic.co/t/how-to-convert-a-list-of-string-to-a-list-of-date-in-filter/47886/3 "2016-04-20T10:47:57Z")
Thank you @magnusbaeck. I've corrected the mistake. But it still failed.
Here are what I've tried
The pipeline was `input(jdbc) - filter(mutate/ruby) - output(es)`
- Split the `valid_dates` string in filter and specify the mappings template in output es
```auto
filter {
mutate {
split => { "valid_dates" => "," }
}
}
output {
elasticsearch {
index => "newmall"
document_type => "shop"
document_id => "%{docid}"
template => "/home/es/logstash-2.2.2/bin/templates/newmall.json"
hosts => "10.10.20.143:9201"
}
}
```
And the template
```auto
{
"template": "newmall",
"mappings": {
"shop": {
"properties": {
"valid_dates": {
"type": "date"
}
}
}
}
```
But at last the type of `valid_dates` in es was string.
- Use both mutate and ruby in filter
```json
filter {
mutate => {
split => { "valid_dates" => "," }
}
ruby {
code => "require 'date'
event['valid_dates']=event['valid_dates'].map {|dt| DateTime.strptime(dt,'%Y-%m-%d %H:%M:%S')}"
}
}
```
The error was
```auto
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
Ruby exception occurred: invalid date {:level=>:error}
Ruby exception occurred: invalid date {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `map' for nil:NilClass {:level=>:error}
```
It seemed that `valid_dates` didn't turn into array, and was recognized as null.
- Use ruby only
```auto
ruby {
code => "require 'date'
event['valid_dates']=event['valid_dates'].split(',')
event['valid_dates']=event['valid_dates'].map {|dt| DateTime.strptime(dt,'%Y-%m-%d %H:%M:%S')}"
}
```
The error was
```auto
Ruby exception occurred: undefined method `split' for nil:NilClass {:level=>:error}
Ruby exception occurred: invalid date {:level=>:error}
Ruby exception occurred: invalid date {:level=>:error}
Ruby exception occurred: undefined method `split' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `split' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `split' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `split' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `split' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `split' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `split' for nil:NilClass {:level=>:error}
Ruby exception occurred: undefined method `split' for nil:NilClass {:level=>:error}
```
It seemed that ruby has recognized `valid_dates` as null. But in the first condition the mutate filter has split the field correctly.
---
### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [April 20, 2016, 11:05am UTC](https://discuss.elastic.co/t/how-to-convert-a-list-of-string-to-a-list-of-date-in-filter/47886/4 "2016-04-20T11:05:41Z")
What does the event look like? Use a `stdout { codec => rubydebug }` output to find out.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 5:01am UTC](https://discuss.elastic.co/t/how-to-convert-a-list-of-string-to-a-list-of-date-in-filter/47886/5 "2017-07-06T05:01:29Z")