Altova MapForce 2022 Basic Edition

The group-by function creates groups of records according to some grouping key that you specify.

mf-func-group-by

For example, in the abstract transformation illustrated below, the grouping key is "Department". Since there are three unique departments in total, applying the group-by function would create three groups:

mf_group-by

 

Languages

Built-in, C++, C#, Java, XSLT 2.0, XSLT 3.0.

 

Parameters

Name

Description

nodes/rows

This input must receive a connection from a mapping item that provides a sequence of zero or more values. For example, the connection may originate from a source XML item.

key

The key by which to group items.

 

Example

Let's assume that your source data is an XML file with the following content (note that, in the code listing below, the namespace and XML declarations were removed for simplicity).

 

<company>
  <person department="Administration" name="Vernon Callaby"/>
  <person department="Marketing" name="Susi Sanna"/>
  <person department="Engineering" name="Michelle Butler"/>
  <person department="Engineering" name="Fred Landis"/>
  <person department="Administration" name="Frank Further"/>  
</company>

 

The business requirement is to group person records by department. To achieve this, the following mapping invokes the group-by function, and supplies department as key.

mf_group-by_map

The mapping result is as follows:

 

<groups>
  <group>
    <record key="Administration" value="Vernon Callaby"/>
    <record key="Administration" value="Frank Further"/>
  </group>
  <group>
    <record key="Marketing" value="Susi Sanna"/>
  </group>
  <group>
    <record key="Engineering" value="Michelle Butler"/>
    <record key="Engineering" value="Fred Landis"/>
  </group>
</groups>

 

This example, together with other grouping examples, is part of the following mapping file: <Documents>\Altova\MapForce2022\MapForceExamples\Tutorial\GroupingFunctions.mfd. Remember to click the Preview mf_ic_preview button applicable to the function you want to preview, before clicking the Output tab.

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