KTHLARGESTIF Function

Extracts the ranked value from the values in a column, where k=1 returns the maximum value, when a specified condition is met. The value for k must be between 1 and 1000, inclusive.

KTHLARGESTIF calculations are filtered by a conditional applied to the group.

For purposes of this calculation, two instances of the same value are treated as separate values. So, if your dataset contains three rows with column values 10, 9, and 9, then KTHLARGEST returns 9 for k=2 and k=3.

Input column can be of Integer or Decimal type. Non-numeric data in the column is ignored. If a row contains a missing or null value, it is not factored into the calculation.

NOTE: When added to a transform, this function is applied to the current sample. If you change your sample or run the job, the computed values for this function are updated. Transforms that change the number of rows in subsequent recipe steps do not affect the values computed for this step.

To perform a simple kth largest calculation without conditionals, use the KTHLARGEST function. See KTHLARGEST Function.

Basic Usage

pivot value: KTHLARGESTIF(POS_Sales, 1, DayOfWeek == 'Saturday') group:storeNbr limit:1

Output: Generates a two-column table containing the unique values for storeNbr and the top value (rank=1) from the POS_Sales column for each storeNbr when the DayOfWeek value is Saturday. The limit parameter defines the maximum number of output columns.

Syntax

pivot value:LISTIF(col_ref, limit, test_expression) [group:group_col_ref] [limit:limit_count]

ArgumentRequired?Data TypeDescription
col_refYstringReference to the column you wish to evaluate.
k_integerYintegerThe ranking of the value to extract from the source column
test_expressionYstringExpression that is evaluated. Must resolve to true or false

For more information on syntax standards, see Language Documentation Syntax Notes.

For more information on the group and limit parameter, see Pivot Transform.

col_ref

Name of the column whose values you wish to use in the calculation. Column must be a numeric (Integer or Decimal) type.

Usage Notes:

Required?Data TypeExample Value
YesString that corresponds to the name of the columnmyValues

k_integer

Integer representing the ranking of the value to extract from the source column.

NOTE: The value for k must be an integer between 1 and 1,000 inclusive.

  • k=1 represents the maximum value in the column.
  • If k is greater than or equal to the number of values in the column, the minimum value is returned.
  • Missing and null values are not factored into the ranking of k.

test_expression

This parameter contains the expression to evaluate. This expression must resolve to a Boolean (true or false) value.

Usage Notes:

Required?Data TypeExample Value
YesString expression that evaluates to true or false(LastName == 'Mouse' && FirstName == 'Mickey')

Examples

Example - Second-most measurements for a specific city

This example illustrates how to use the conditional ranking function KTHLARGESTIF in your recipes.

Source:

Here is some example weather data:

datecityrain_cmtemp_Cwind_mph
1/23/17Valleyville0.0012.86.7
1/23/17Center Town0.319.45.3
1/23/17Magic Mountain0.000.07.3
1/24/17Valleyville0.2517.23.3
1/24/17Center Town0.541.17.6
1/24/17Magic Mountain0.325.08.8
1/25/17Valleyville0.023.36.8
1/25/17Center Town0.833.35.1
1/25/17Magic Mountain0.59-1.76.4
1/26/17Valleyville1.0815.04.2
1/26/17Center Town0.966.17.6
1/26/17Magic Mountain0.77-3.93.0
1/27/17Valleyville1.007.22.8
1/27/17Center Town1.3220.00.2
1/27/17Magic Mountain0.775.65.2
1/28/17Valleyville0.12-6.15.1
1/28/17Center Town0.145.04.9
1/28/17Magic Mountain1.501.10.4
1/29/17Valleyville0.3613.37.3
1/29/17Center Town0.756.19.0
1/29/17Magic Mountain0.603.36.0


Transform:

In this case, you want to find out the second-most measures for rain, temperature, and wind in Center Town for the week.

pivot value:KTHLARGESTIF(rain_cm,2,city == 'Center Town') limit:1

You can see in the preview that the value is 1.32. Before adding it to your recipe, you change the step to the following:

pivot value:KTHLARGESTIF(temp_C,2,city == 'Center Town') limit:1

The value is 20. For wind, you modify it to be the following:

pivot value:KTHLARGESTIF(wind_mph,2,city == 'Center Town') limit:1

Results:

You can choose to add any of these steps to generate an aggregated result. As an alternative, you can use a derive transform to insert these calculated results into new columns.

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