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Excerpt

Computes the rolling unique kth largest value forward or backward of the current row. Inputs can be Integer, Decimal, or Datetime.

For purposes of this calculation, two instances of the same value are treated at one value for k. So, if your dataset contains four rows with column values 1099, and 8, then KTHLARGESTUNIQUE returns 9 for k=2 and 8 for k=3.

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For more information on a non-rolling version of this function, see KTHLARGESTUNIQUE Function.d-s-lang-vs-sql

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Column example:

rollingkthlargestunique(myCol, 2)
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derive type:single value:

rollingkthlargestuniqueROLLINGKTHLARGESTUNIQUE(myCol, 2)

Output: 

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Generates a new column containing the rolling second largest unique value in the myCol column from the first row of the dataset to the current one.

Rows before example:

WrangleTextrollingkthlargestunique(myNumber, 2, 3)
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window value:

rollingkthlargestuniqueROLLINGKTHLARGESTUNIQUE(myNumber, 2, 3)

Output:

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 Generates the new column, which contains the rolling second largest unique value of the current row and the two previous row values in the myNumber column.

Rows before and after example:

window value:rollingkthlargestunique
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window value:value:ROLLINGKTHLARGESTUNIQUE(myNumber, 4, 3, 2)

rollingkthlargestunique(myNumber, 4, 3, 2)

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Output: Generates the new column, which contains the rolling fourth largest unique value of the two previous row values, the current row value, and the two rows after the current one in the myNumber column.

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snippetSyntax

WrangleTextrollingkthlargestunique(col_ref, rowsBefore_integer, rowsAfter_integer) order: order_col [group: group_col]
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window value:

rollingkthlargestuniquevalue:ROLLINGKTHLARGESTUNIQUE(col_ref, rowsBefore_integer, rowsAfter_integer) order: order_col [group: group_col]

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Name of the column whose values are used to compute the function. Inputs must be Integer, Decimal, or Datetime values.

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  • Multiple columns and wildcards are not supported.

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Required?Data TypeExample Value
YesString (column reference to Integer or Decimal values)myColumn

k_integer

Integer representing the ranking of the unique value to extract from the source column. Duplicate values are treated as a single value for purposes of this function's calculation.

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Integers representing the number of rows before or after the current one from which to compute the rolling function, including the current row. For example, if the first value is 5, the current row and the four rows after it are used in the computation. Negative  Negative values for krowsAfter_integer compute the rolling average function from rows preceding the current one.

  • rowBefore=1 generates the current row value only.
  • rowBefore=-1  uses all rows preceding the current one.
  • If rowsAfter is not specified, then the value 0 is applied.
  • If a group parameter is applied, then these parameter values should be no more than the maximum number of rows in the groups.

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