first last element

Question

XSLT XML Question.

Looking into a simple transformation. I have simple index xml input. I have to output the the first and last element with a for each chapter. AS shown

Answer 1

Updated to take advantage of a cleaner predicate - thanks to @SeanB.Durkin.

I. XSLT 1.0 Solution

When this XSLT:

...is applied to the original XML:

  Chapter01
  Chapter01
  Chapter01
  Chapter01
  Chapter01
  Chapter01
  Chapter02
  Chapter02
  Chapter02
  Chapter02
  Chapter02
  Chapter02
  Chapter03
  Chapter03
  Chapter03
  Chapter03
  Chapter03
  Chapter03

...the desired result is produced:

  Chapter01
  Chapter01
  Chapter02
  Chapter02
  Chapter03
  Chapter03

Explanation:

• Note the proper use of Muenchian Grouping to determine the unique elements by their value.
• For each unique element, two elements are copied: the first and last from the group that contains the unique value.

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II. XSLT 2.0 Solution

Note that in XSLT 2.0, the solution becomes even simpler.

When this XSLT:

...is applied to the original XML, the same desired result is produced:

  Chapter01
  Chapter01
  Chapter02
  Chapter02
  Chapter03
  Chapter03

Explanation:

• The same methodology is applied, but instead of Muenchian Grouping, XSLT 2.0's for-each-group element and current-group() instruction are used.