Kibana Scripted fields

I am trying to create scripted filed in kibana by combing two fields one is string and one is numeric using below script but it is giving hostname should be numeric error.
doc['host name'].value + doc['app_id'].value

Can any one provide inputs to create scripted field combination of string and integer.

Hi Srikanth,

it depends on the script-language you are using. In Kibana 4.x, you can only use "expression" -language which only works for numerical operations. So that won't work for your use case.

In Kibana 5, you will be able to do string operations with the "painless" or "groovy" scripting languages, which will allow you to do string concatenations. Version 5 is currently in beta.

Thanks,