ROLLINGLIST Function
Computes the rolling list of values forward or backward of the current row within the specified column and returns an array of these values.
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 count of distinct values 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 three optional integer parameters that determine the maximum number of values and the window backward and forward of the current row.
By default, the list is limited to
1000
values. To change the maximum number of values, specify a value for thelimit
parameter.For the window parameters, the default values are
1
and0
, which computes the rolling function from the current row back to the first row of the dataset.
This function works with the Window transform. See Window Transform.
For more information on a nonrolling version of this function, see LIST Function.
Wrangle vs. SQL: This function is part of Wrangle, a proprietary data transformation language. Wrangle is not SQL. For more information, see Wrangle Language.
Basic Usage
Column example:
rollinglist(myCol)
Output: Returns the rolling list of values in the myCol
column from the first row of the dataset to the current one.
Rows before example:
rollinglist(myNumber, 5, 20)
Output: Returns the rolling list of values of the current row and the twenty previous row values in the myNumber
column, with a limit of 5 total values.
Rows before and after example:
rollinglist(myNumber, 20, 299, 200)
Output: Returns the rolling list of values from the previous 299 rows, the current row value, and the 200 rows after the current one in the myNumber
column, with a limit of 20 total values.
Syntax and Arguments
rollinglist(col_ref, rowsBefore_integer, rowsAfter_integer) order: order_col [group: group_col]
Argument  Required?  Data Type  Description 

col_ref  Y  string  Name of column whose values are applied to the function 
limit_int  N  integer  Maximum number of values to extract into the list array. From 
rowsBefore_integer  N  integer  Number of rows before the current one to include in the computation 
rowsAfter_integer  N  integer  Number 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 Type  Example Value 

Yes  String (column reference to Integer or Decimal values)  myColumn 
limit_int
Nonnegative integer that defines the maximum number of values to extract into the list array.
Note
If specified, this value must between 1 and 1000, inclusive.
Note
Do not use the limiting argument in a LIST
function call on a flat aggregate, in which all values in a column have been inserted into a single cell. In this case, you might be able to use the limit argument if you also specify a group
parameter. Misuse of the LIST
function can cause the application to crash.
Usage Notes:
Required?  Data Type  Example Value 

No  Integer  50 
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 rowsAfter_integer
compute the rolling 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 value0
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 Type  Example Value 

No  Integer  4 
Examples
Tip
For additional examples, see Common Tasks.
Example  Recent Finishers by Boat Type
The following dataset includes the finishing times for each boat in a race. As part of the race, each boat may be assigned one or more penalties in terms of seconds. So, the total time for the race is computed by adding two columns.
You are interested in the list of recent finishers by each finishing time.
Source:
id  pilotName  boatType  raceTime  racePenalties 

1  Schmidt  Sunfish  4573.8  53 
2  Bolt  Laser  4934.21  11 
3  Masters  Force 5  4446.89  70 
4  Jamison  Force 5  4355.79  31 
5  Williams  Sunfish  4675.86  15 
6  Hobart  Laser  5077.5  50 
7  Millingham  Laser  4940.09  54 
8  Nelson  Force 5  5116.14  56 
9  Greene  Sunfish  5105.94  5 
10  Danielson  Laser  4964.03  18 
11  Cooper  Force 5  5281.55  13 
12  Stevens  Laser  5176.35  0 
13  Young  Sunfish  5038.11  16 
14  Thompson  Force 5  5252.9  62 
15  McDonald  Laser  5052.24  20 
16  O'Roarke  Sunfish  5080.76  45 
17  Collins  Sunfish  5176.09  10 
18  Wright  Laser  5391.61  34 
19  Black  Sunfish  5023.32  32 
20  Bush  Force 5  5200.37  28 
Transformation:
Compute the total time for each racer by summing the raceTime
column and the racePenalties
column:
Transformation Name 


Parameter: Formula type  Single row formula 
Parameter: raceTime + racePenalties  FCTN(input) 
Parameter: New column name  'totalRaceTime' 
You can then compute the list of recent finishers by boat type, automatically sorting the generated lists by the totalRaceTime
column:
Transformation Name 


Parameter: Formula type  Multiple row formula 
Parameter: Formula  rollinglist(boatType, 10, 4, 0) 
Parameter: Order rows by  totalRaceTime 
Parameter: New column name  'last5FinisherBoatTypes' 
Results:
id  pilotName  boatType  last5FinisherBoatTypes  raceTime  racePenalties  totalRaceTime 

4  Jamison  Force 5  ["Force 5"]  4355.79  31  4386.79 
3  Masters  Force 5  ["Force 5","Force 5"]  4446.89  70  4516.89 
1  Schmidt  Sunfish  ["Force 5","Force 5","Sunfish"]  4573.8  53  4626.8 
5  Williams  Sunfish  ["Force 5","Force 5","Sunfish","Sunfish"]  4675.86  15  4690.86 
2  Bolt  Laser  ["Force 5","Force 5","Sunfish","Sunfish","Laser"]  4934.21  11  4945.21 
10  Danielson  Laser  ["Force 5","Sunfish","Sunfish","Laser","Laser"]  4964.03  18  4982.03 
7  Millingham  Laser  ["Sunfish","Sunfish","Laser","Laser","Laser"]  4940.09  54  4994.09 
13  Young  Sunfish  ["Sunfish","Laser","Laser","Laser","Sunfish"]  5038.11  16  5054.11 
19  Black  Sunfish  ["Laser","Laser","Laser","Sunfish","Sunfish"]  5023.32  32  5055.32 
15  McDonald  Laser  ["Laser","Laser","Sunfish","Sunfish","Laser"]  5052.24  20  5072.24 
9  Greene  Sunfish  ["Laser","Sunfish","Sunfish","Laser","Sunfish"]  5105.94  5  5110.94 
16  O'Roarke  Sunfish  ["Sunfish","Sunfish","Laser","Sunfish","Sunfish"]  5080.76  45  5125.76 
6  Hobart  Laser  ["Sunfish","Laser","Sunfish","Sunfish","Laser"]  5077.5  50  5127.5 
8  Nelson  Force 5  ["Laser","Sunfish","Sunfish","Laser","Force 5"]  5116.14  56  5172.14 
12  Stevens  Laser  ["Sunfish","Sunfish","Laser","Force 5","Laser"]  5176.35  0  5176.35 
17  Collins  Sunfish  ["Sunfish","Laser","Force 5","Laser","Sunfish"]  5176.09  10  5186.09 
20  Bush  Force 5  ["Laser","Force 5","Laser","Sunfish","Force 5"]  5200.37  28  5228.37 
11  Cooper  Force 5  ["Force 5","Laser","Sunfish","Force 5","Force 5"]  5281.55  13  5294.55 
14  Thompson  Force 5  ["Laser","Sunfish","Force 5","Force 5","Force 5"]  5252.9  62  5314.9 
18  Wright  Laser  ["Sunfish","Force 5","Force 5","Force 5","Laser"]  5391.61  34  5425.61 