14.13.9 Joining PGX Frames

You can join two frames whose rows are correlated through one of the columns using the join functionality. This allows us to combine frames by checking for equality between rows for a specific column.

The following example shows joining two PgxFrames exampleFrame and moreInfoFrame on the name column by calling the join method.

• JShell
• Java

opg4j> exampleFrame.join(moreInfoFrame, "name", "leftFrame", "rightFrame").print()

exampleFrame.join(moreInfoFrame, "name", "leftFrame", "rightFrame").print();

The result may appear as shown:

+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| leftFrame_name | leftFrame_age | leftFrame_salary | leftFrame_married | leftFrame_tax_rate | leftFrame_random | leftFrame_date_of_birth | rightFrame_name | rightFrame_title             | rightFrame_reports |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| John           | 27            | 4133300.0        | true              | 11.0               | 123456782        | 1985-10-18              | John            | Software Engineering Manager | 5                  |
| Albert         | 23            | 5813000.5        | false             | 12.0               | 124343142        | 2000-01-14              | Albert          | Sales Manager                | 10                 |
| Emily          | 24            | 9380080.5        | false             | 13.0               | 128973221        | 1910-07-30              | Emily           | Operations Manager           | 20                 |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

The joined frame contains the columns of the two frames involved in the operation for the rows with the same name.

Note:

The column prefixes specified in the join() call, leftFrame and rightFrame.