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Trifacta Dataprep


Contents:

On April 28, 2021, Google is changing the required permissions for attaching IAM roles to service accounts. If you are using IAM roles for your Google service accounts, please see Changes to User Management.

   

This example demonstrates the following two functions:

  • RANK - Generates a ranked order of values, ranked within a group. 
    • If there are three tie values in a group, the next ranking is three more than the tie values.
    • See RANK Function.
  • DENSERANK - Generates a ranked order of values, ranked within a group.
    • If there are three tie values in a group, the next ranking is one more than the tie values.
    • See DENSERANK Function.

Source:

The following dataset contains lap times for three racers in a four-lap race. Note that for some racers, there are tie values for lap times.

RunnerLapTime
Dave172.2
Dave273.31
Dave372.2
Dave470.85
Mark171.73
Mark271.73
Mark372.99
Mark470.63
Tom174.43
Tom270.71
Tom371.02
Tom472.98


Transformation:

You can apply the RANK() function to the Time column, grouped by individual runner:

Transformation Name Window
Parameter: Formulas RANK()
Parameter: Group by Time
Parameter: Order by Runner

You can use the DENSERANK() function on the same column, grouping by runner:

Transformation Name Window
Parameter: Formulas DENSERANK()
Parameter: Group by Runner
Parameter: Order by Time

Results:

After renaming the columns, you have the following output:

RunnerLapTimeRankRank-Dense
Mark470.6311
Mark171.7322
Mark271.7322
Mark372.9943
Tom270.7111
Tom371.0222
Tom472.9833
Tom174.4344
Dave470.8511
Dave172.222
Dave372.222
Dave273.3143


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