Projection

Creates a new DataFrame that contains only the selected columns. The order of the columns is specified by user. Each column can be optionally renamed. Each column can be selected many times, but in the resulting DataFrame column names cannot be duplicated.

Also returns a Transformer that can be later applied to another DataFrame with a Transform operation.

Since: Seahorse 1.2.0

Input

Port Type Qualifier Description
0 DataFrame The DataFrame to select columns from.

Output

Port Type Qualifier Description
0 DataFrame The DataFrame containing the selected columns (and only them).
1 Transformer The Transformer that allows to apply the operation on other DataFrames using the Transform.

Parameters

Name Type Description
projection columns Parameters Sequence The sequence of column projection descriptions (original column: SingleColumnSelector, rename column: Single Choice - possible values: ["No", "Yes"], column name: String - valid only if rename column is set to "Yes") defining the selection, order and optionally new names of columns. When a column selected by name or by index does not exist, ColumnDoesNotExistException is thrown.

Example

Parameters

Name Value
projection columns Select columns: price, city, city (renamed to location)

Input

city beds price
CityA 4.0 695611.0
CityC 2.0 294691.0
CityB 3.0 430784.0
CityB 2.0 336677.0
CityA 3.0 584639.0
CityA 4.0 579560.0

Output

price city location
695611.0 CityA CityA
294691.0 CityC CityC
430784.0 CityB CityB
336677.0 CityB CityB
584639.0 CityA CityA
579560.0 CityA CityA