columns

A map that defines the schema of the columns within a DataFrameSchema.

The key represents the name of the column, while the value is a ColumnSchema describing the structure, type, and properties of the column.

The value can be one of the following:

• ColumnSchema.Value: Represents a value column, including its type and nullability.

• ColumnSchema.Group: Represents a group of columns, containing their schemas as a nested DataFrameSchema.

• ColumnSchema.Frame: Represents a frame column (column of dataframes) containing their DataFrameSchema.

This map provides an ordered representation of the schema that accurately describes the names and corresponding structure of all columns in a dataframe.