SimpleLoop
Creates a loop based on an input map element.
This function specifies that the output map element associated with the loop expression tab is to loop corresponding to the value of the input map element argument expression.
When an input map element is mapped to an output map element that loops, the SimpleLoop function is automatically created at the nearest ancestor looping output element to define the loop.
If no sort keys are specified, the order of the output is the same order as the input elements.
This function can only be used in the Loop tab or as part of an Aggregate expression.
Arguments
| Input Map Element | Add a looping element from the input structure. |
| Filter | Specify an expression that returns a Boolean. This expression is evaluated for each instance of the loop. If this filter expression returns true, the instance is included in the loop. If it returns false, the instance is excluded from the loop. |
| Sort Keys | Use the AscendingSort or DescendingSort function to sort loop iterations. You can use as many as needed. |
| Contexts | Specify the context using the EnclosingContext or NestedContext function. EnclosingContext specifies the output map element that encloses this loop. If not specified, the nearest looping ancestor map element is used. |
Properties
| Distinct Option | Select Direct Child if you
want to select the Distinct Child
Element in a list of direct child elements of the
looping input element, or Element
XPath if you want to enter an XPath to reference a
different input element. Information noteNote: This option is available only if
you have installed the TPS-4177 patch or a later cumulative
patch delivered by Talend. For more information, contact Talend
support.
|
| Distinct Child Element | Select the input map element to be used to select distinct
values. If selected, only iterations of the loop that have distinct
values for the selected element are considered. If this is not
selected, all instances of the input map element are considered. When a loop contains duplicated sub-elements, the Distinct Child Element field provides a filter to get only one instance of each distinct sub-element. |
| Disable sort by distinct child | If you have specified a Distinct Child Element, select this check box to keep the default sorting instead of sorting by distinct child. If this check box is not selected, the output is sorted in ascending order based on the value of the Distinct Child Element. |
| Emit Loop Instance If Empty | Select this check box if you want to generate a single instance of this loop in the output if there are no instances of the input loop. This is useful to generate loop instance with a default value. |
| Stream Input | Select this check box to allow the input data for this loop to be
broken into chunks and processed separately. Without this option,
the entire input data is read into memory before the transformation
is executed. When Stream
Input is selected, since the transformation is
processed in segments, input data of unlimited size can be
processed. When Stream Input is selected there are some significant restrictions on the transformation expressions. For more information, see Streaming Execution. |