Extension properties docs #1246
Conversation
AndreiKingsley
commented
Jun 11, 2025
AndreiKingsley
commented
- Closes Add more info about extensions in docs. #1244.
There was a problem hiding this comment.
Very nice extension :) hopefully it will make it a lot clearer for users.
See #661 for most of my comments haha
| @@ -24,6 +24,9 @@ Explore our structured, in-depth guides to steadily improve your Kotlin DataFram | |||
|
|
|||
| <img src="quickstart_preview.png" border-effect="rounded" width="705"/> | |||
|
|
|||
| * [](extensionPropertiesApi.md) — learn about extension properties for `DataFrame` | |||
There was a problem hiding this comment.
if you're referring to the library "DataFrame", if you're referring to the type "DataFrame"
There was a problem hiding this comment.
What? DataFrame is a type/object here, and there are extensions for it.
There was a problem hiding this comment.
then please add a link :)
| @@ -88,8 +88,8 @@ columns. | |||
| Column selectors are widely used across operations — one of the simplest examples is `.select { }`, which returns a new | |||
| DataFrame with only the columns chosen in Columns Selection expression. | |||
|
|
|||
| After executing the cell where a `DataFrame` variable is declared, an extension with properties for its columns is | |||
| automatically generated. | |||
| After executing the cell where a `DataFrame` variable is declared, | |||
There was a problem hiding this comment.
unnecessary information IMHO. I mean there's mention about Row API below, I think it's enough for begin.
|
|
||
| Some operations use `RowExpression`, i.e., expression that applies for all `DataFrame` rows. For example `.filter { }` | ||
| that returns a new `DataFrame` with rows that satisfy a condition given by row expression. | ||
| Some operations use [DataRow API](DataRow.md), with expressions and conditions |
| that returns a new `DataFrame` with rows that satisfy a condition given by row expression. | ||
| Some operations use [DataRow API](DataRow.md), with expressions and conditions | ||
| that apply for all `DataFrame` rows. | ||
| For example, `.filter { }` that returns a new `DataFrame` with rows \ |
| ) | ||
| ``` | ||
|
|
||
| Read the `DataFrame` from the CSV file and specify the schema with `convertTo`: |
There was a problem hiding this comment.
hmm maybe also mention cast<>()? convertTo is safer but also heavier
| val df = DataFrame.readCsv("example.csv").convertTo<Person>() | ||
| ``` | ||
|
|
||
| Extensions for this `DataFrame` will be generated automatically by plugin, |
|
|
||
| Moreover, new extensions will be generated on-the-fly after each schema change: | ||
| by changing any column [name](rename.md) | ||
| or [type](convert.md), or [add](add.md) a new one. |
| Moreover, new extensions will be generated on-the-fly after each schema change: | ||
| by changing any column [name](rename.md) | ||
| or [type](convert.md), or [add](add.md) a new one. | ||
| For example, rename the "name" column into "firstName" and then we can use `firstName` extensions |
There was a problem hiding this comment.
My logic is simple:
name is an extension property (DataColumn/row value).
"name" is a column.
There was a problem hiding this comment.
hmm but then "" could both refer to a column and a column name, which is also confusing IMO. I'd be okay with the column and the column accessor being written the same.
| To find out how to use this API in your environment, check out [Working with Data Schemas](schemas.md) | ||
| or jump straight to [Data Schemas in Gradle projects](schemasGradle.md), | ||
| or [Data Schemas in Jupyter notebooks](schemasJupyter.md). | ||
| See [Kotlin DataFrame Compiler Plugin Example](https://github.com/Kotlin/dataframe/tree/plugin_example/examples/kotlin-dataframe-plugin-example) |
There was a problem hiding this comment.
can you make the name a bit shorter here as well?
