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6 changes: 5 additions & 1 deletion docs/StardustDocs/topics/adjustSchema.md
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[`DataFrame`](DataFrame.md) interface has type argument `T` that doesn't affect contents of [`DataFrame`](DataFrame.md),
but marks [`DataFrame`](DataFrame.md) with a type that represents data schema that this [`DataFrame`](DataFrame.md) is supposed to have.
This argument is used to generate [extension properties](extensionPropertiesApi.md) for typed data access.
This argument is used to generate [extension properties](extensionPropertiesApi.md) for typed data access.

Another place where this argument has special role is [interop with data classes](collectionsInterop.md#interop-with-data-classes):
* `List<T>` -> `DataFrame<T>`: [toDataFrame](createDataFrame.md#todataframe)
* `DataFrame<T>` -> `List<T>`: [toList](toList.md)

Actual data in [`DataFrame`](DataFrame.md) may diverge from compile-time schema marker `T` due to dynamic nature of data inside [`DataFrame`](DataFrame.md).
However, at some points of code you may know exactly what [`DataFrame`](DataFrame.md) schema is expected.
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