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Altova MapForce 2021 Professional Edition

The group-into-blocks function creates equal groups that contain exactly N items, where N is the value you supply to the block-size argument. Note that the last group may contain N items or less, depending on the number of items in the source.

mf-func-group-into-blocks

In the example below, block-size is 2. Since there are five items in total, each group contains exactly two items, except for the last one.

mf_group-into-blocks

 

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, a CSV field, a database record, and so on.

block-size

Specifies the size of each group

 

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 into blocks of two items each. To achieve this, the following mapping invokes the group-into-blocks function, and supplies the integer value "2" as block-size.

mf_group-into-blocks_map

The mapping result is as follows:

 

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

 

Note that the last group contains only one item, since the total number of items (5) cannot be divided evenly by 2.

 

This example, together with other grouping examples, is part of the following mapping file: <Documents>\Altova\MapForce2021\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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