[jira] [Commented] (FREEMARKER-144) [freemarker-cli] Proof Of Concept for providing DataFrames

["Siegfried Goeschl (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FREEMARKER-144?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17138736#comment-17138736 ] 

Siegfried Goeschl commented on FREEMARKER-144:
----------------------------------------------

The code supports 

* JSON => GsonTool => DataFrameTool
* CSV => CSVTool => DataFrameTool
* Excel => ExcelTool => DataFrameTool

but I'm not entirely happy with it

* I introduced a `Table` and I'm not sure if I need it in the long run
* I want to integrate https://github.com/nRo/DataFrame/issues/21 to support temporal column types
* The existing Excel integration is a bit rough

Having said that it is a POC and it is working so far

> [freemarker-cli] Proof Of Concept for providing DataFrames
> ----------------------------------------------------------
>
>                 Key: FREEMARKER-144
>                 URL: https://issues.apache.org/jira/browse/FREEMARKER-144
>             Project: Apache Freemarker
>          Issue Type: Task
>            Reporter: Siegfried Goeschl
>            Assignee: Siegfried Goeschl
>            Priority: Major
>
> Sometime users need to massage tabular data coming from CSV or an Excel sheet, eg.. joining on columns
> * There is some ad-hoc code in the FreeMarker Generator CSV tool 
> * I had a look at available DataFrame libraries (see https://medium.com/@thijser/doing-cool-data-science-in-java-how-3-dataframe-libraries-stack-up-5e6ccb7b437)
> I finally found [nRo/DataFrame|https://github.com/nRo/DataFrame] and it would make a good fit
> * Comes with MIT licence
> * Depends only on `antlr4-runtime` and `slf4j`
> * It's API would fit nicely into a FreeMarker Template
> * It provides a DataFrame implementation and some basic transformations
> * It currently does not support temporal column types
> What I would like to implement is
> * Reading CSV & Excel into a DataFrame
> * Write a DataFrame to CSV



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