DataFrames extension

This module simply extends Core's reconstruct_table method to:

• work with DataFrames

• not copy columns unless it is necessary to do so

• allow passing through known kwargs to the constructor

In the future, if we ever end up defining ApplyToFeatures on a table, then we will need to add some form of method for that... which will likely entail adding an extra positional argument to the reconstruct_table method, and checking whether other_column_namesis equal tosetdiff(Tables.columnnames(input), geometry_column_names).

If it is not then we will have to reconstruct the whole DataFrame from the GI.Feature named-tuple row table representation.

module GeometryOpsDataFramesExt

import GeometryOpsCore
using DataFrames

GeometryOpsCore.used_reconstruct_table_kwargs(::DataFrames.DataFrame) = (:copycols,)

function GeometryOpsCore.reconstruct_table(
        input::DataFrames.DataFrame, geometry_column_names, geometry_columns,
        other_column_names, args...;
        copycols = true, kwargs...
    )

Create a new dataframe, let the rest be the same

    new_df = DataFrame(input; copycols)

Copy over the geometry columns

    for (colname, col) in zip(geometry_column_names, geometry_columns)
        new_df[!, colname] = col
    end

The other columns were already copied over by the constructor, so we're done. Metadata is set in the _apply_table method.

    return new_df
end

end

---

This page was generated using Literate.jl.