ROLLINGMODE Function

Computes the rolling mode (most common value) forward or backward of the current row within the specified column.
  • If an input value is missing or null, it is not factored in the computation. For example, for the first row in the dataset, the rolling mode of previous values is undefined.
  • The row from which to extract a value is determined by the order in which the rows are organized based on the order parameter.

    If you are working on a randomly generated sample of your dataset, the values that you see for this function might not correspond to the values that are generated on the full dataset during job execution.

  • The function takes a column name and two optional integer parameters that determine the window backward and forward of the current row.
    • The default integer parameter values are -1 and 0, which computes the rolling function from the current row back to the first row of the dataset.
  • This function works with the following transforms:

For more information on a non-rolling version of this function, see MODE Function.

Basic Usage

Column example:

derive type:single value:ROLLINGMODE(myCol)

Output: Generates a new column containing the rolling mode of all values in the myCol column from the first row of the dataset to the current one.

Rows before example:

window value:ROLLINGMODE(myNumber, 3)

Output: Generates the new column, which contains the rolling mode of the current row and the two previous row values in the myNumber column.

Rows before and after example:

window value:ROLLINGMAX(myNumber, 3, 2)

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

Syntax

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

ArgumentRequired?Data TypeDescription
col_refYstringName of column whose values are applied to the function
rowsBefore_integerNintegerNumber of rows before the current one to include in the computation
rowsAfter_integerNintegerNumber of rows after the current one to include in the computation

For more information on the order and group parameters, see Window Transform.

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

col_ref

Name of the column whose values are used to compute the function.

  • Multiple columns and wildcards are not supported.

Usage Notes:

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

rowsBefore_integer, rowsAfter_integer

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 values for k compute the rolling average 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.

Usage Notes:

Required?Data TypeExample Value
NoInteger4

Examples

Example - Counting most common coin flips

In the following table, 20 coin flips are tabulated. You want to capture a rolling evaluation of the most common value.

Source:

TurnResult
1heads
2heads
3tails
4heads
5heads
6tails
7tails
8heads
9tails
10heads
11tails
12heads
13tails
14heads
15heads
16tails
17tails
18tails
19heads
20heads


Transform:

To use the ROLLINGMODE function, the results need to be converted to numeric values:

set col: Result value: if(Result == 'heads', 0, 1)

Now calculate the ROLLINGMODE for the preceding five values for each row:

derive type: multiple value: rollingmode(Result, 4, 0) order: Turn as: 'mostCommonLast5'

You can now convert the binary values back to text information:

set col: mostCommonLast5 value: if(mostCommonLast5 == 0, 'heads-last5', 'tails-last5')


Results:

TurnResultmostCommonLast5
1headsheads-last5
2headsheads-last5
3tailsheads-last5
4headsheads-last5
5headsheads-last5
6tailsheads-last5
7tailstails-last5
8headsheads-last5
9tailstails-last5
10headstails-last5
11tailstails-last5
12headsheads-last5
13tailstails-last5
14headsheads-last5
15headsheads-last5
16tailsheads-last5
17tailstails-last5
18tailstails-last5
19headstails-last5
20headstails-last5

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