xsl:for-each-group

select

expression

Expression to select nodes/values.

group-by?

expression

Groups together all items having the same value for a grouping key. The grouping key may have multiple values (a sequence of values) in which case the item is added to more than one group.

group-adjacent?

expression

Groups together all items having the same value for a grouping key, provided that they are also adjacent in the input sequence. This is useful when you need to wrap a new element around a sequence of related elements in the source documents, for example a consecutive sequence of <bullet> elements. In this case the grouping key must be single-valued.

group-starting-with?

pattern

Processes the items in the supplied sequence in turn, starting a new group whenever one of the items matches a specified pattern. This is useful, for example, when matching an <h2> element and its following <p> elements.

group-ending-with?

pattern

Processes the items in the supplied sequence in turn, closing the current group whenever one of the items matches a specified pattern. This is useful when matching a sequence of items in which the last item in the group carries some distinguishing attribute such as continued="no".

break-when?

expression

Experimental addition in 4.0; available only if syntax extensions are enabled. The value of the attribute is an expression, which must return a boolean. The expression is supplied with two variables, namely (a) $group which is set to the contents of the current group, and (b) $next which is set to the next item. The expression returns false if the new item is to be added to the end of the current group, or true if the current group is complete and the new item is to become the first item in a new current group. For example break-when="sum($group/@page-count) gt 100" starts a new group when the size of the current group passes some threshold.

composite?

boolean

Can be used when grouping using either group-by or group-adjacent. If set to yes, then the group-by and group-adjacent expressions may evaluate to a sequence, and grouping is done by comparing the entire sequence. If set to no (the default), then when group-by evaluates to a sequence, the relevant item has multiple grouping keys and goes in multiple groups; with group-adjacent, a sequence-valued grouping key is then an error.

collation?

{ uri }

The name of a collating sequence, used when comparing grouping keys. Can be used when grouping using either group-by or group-adjacent. If present it must be a collation URI that uses the scheme and path http://www.w3.org/2013/collation/UCA, in which case it requests use of the Unicode Collation Algorithm, or is a collation otherwise recognized by Saxon: see Sorting and collations.