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  • 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 non-null 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 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:Window transform. See Window Transform.
  • Set Transform
  • Derive Transform

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

D s lang vs sql

D s
snippetBasic

Column example:

ROLLINGCOUNTA
d-codelang-syntax
RawWrangletrue
Typeref
showNotetrue
WrangleTextderive type:single value:
rollingcounta(myCol)

rollingcounta(myCol)

Output: 

...

Returns rolling count of non-null values in the myCol column

...

.

Rows before example:

ROLLINGCOUNTA
d-codelang-syntax
RawWrangletrue
Typeref
showNotetrue
WrangleTextwindow value:
rollingocounta(myNumber, 3)

rollingocounta(myNumber, 3)

Output:

...

Returns the rolling count of non-null values of the current row and the three previous row values in the myNumber column.

Rows before and after example:

ROLLINGCOUNTA
d-code-lang-syntax
RawWrangletrue
Typeref
showNotetrue
WrangleTextwindow value:
rollingcounta(myNumber, 3, 2)

rollingcounta(myNumber, 3, 2)

Output:

...

 Returns the rolling count of non-nulls from the three previous row values, the current row value, and the two rows after the current one in the myNumber column.     

D s
snippetSyntax

ROLLINGCOUNTA
d-code-lang-syntax
RawWrangletrue
Typesyntax
showNotetrue
WrangleTextwindow value:
rollingcounta(col_ref, rowsBefore_integer, rowsAfter_integer) order: order_col [group: group_col]

rollingcounta(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

...

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 five rows before it are used in the computation. Negative  Negative values for rowsAfter_integer compute the rolling function from rows preceding the current one.

  • rowBefore=0 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.

...

TimestampmsgTypemsgDescription
15:10:00 PMwarningServer restarted.
15:10:10 PMwarningUnable to locate patterns file.
15:10:20 PM  
15:10:30 PM  
15:10:40 PMerrorCannot connect to data source.
15:10:50 PMerrorCannot open dataset.
15:11:00 PM  
15:11:10 PM  
15:11:20 PMerrorInsufficient permissions to write to target location.
15:11:30 PM  
15:11:40 PMwarningServer restarted.
15:11:50 PMwarningUnable to locate patterns file.
15:12:00 PMerrorData node offline.
15:12:10 PM  
15:12:20 PM  
15:12:30 PMwarningInvalid statement in recipe.
15:12:40 PM  
15:12:50 PM  

TransformTransformation:

You are interested in counting the number of entries for the preceding minute for each row. You add the following:

d-

...

trans
RawWrangletrue
p03Valuerollingcounta(msgType, 5, 0)
Typestep
WrangleTextderive type: multiple value: rollingcounta(msgType, 5, 0) order: Timestamp as: 'rollingcounta_msgType'
p01NameFormula type
p01ValueMultiple row formula
p02NameSort rows by
p02ValueTimestamp
p03NameFormula
p04Value'rollingcounta_msgType'
p04NameNew column name
SearchTermNew formula

Results:

TimestampmsgTypemsgDescriptionrollingcounta_msgType
15:10:00 PMwarningServer restarted.1
15:10:10 PMwarningUnable to locate patterns file.2
15:10:20 PM  2 
15:10:30 PM  
15:10:40 PMerrorCannot connect to data source.3
15:10:50 PMerrorCannot open dataset.4
15:11:00 PM  
15:11:10 PM  
15:11:20 PMerrorInsufficient permissions to write to target location.3
15:11:30 PM  3 
15:11:40 PMwarningServer restarted.3
15:11:50 PMwarningUnable to locate patterns file.3
15:12:00 PMerrorData node offline.4
15:12:10 PM  4 
15:12:20 PM  3 
15:12:30 PMwarningInvalid statement in recipe.4
15:12:40 PM  3 
15:12:50 PM  2 


D s also
labelwindow