collection.slice( )

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4D v19.8

collection.slice( )


collection.slice ( startFrom {; end} ) -> Function result

Parameter	Type	Description
startFrom	Longint	Index to start the search at (included)
end	Longint	End index (not included)
Function result	Collection	New collection containing sliced elements (shallow copy)

Description

The collection.slice( ) method returns a portion of a collection into a new collection, selected from startFrom index to end index (end not included). This method returns a shallow copy of the collection. If the original collection is a shared collection, the returned collection is also a shared collection.

Note: This method does not modify the original collection.

The returned collection contains the element specified by startFrom and all subsequent elements up to, but not including, the element specified by end. If only the startFrom parameter is specified, the returned collection contains all elements from startFrom to the last element of the original collection.

If startFrom < 0, it is recalculated as startFrom:=startFrom+length (it is considered as the offset from the end of the collection).
If the calculated value < 0, startFrom is set to 0.
If end < 0 , it is recalculated as end:=end+length.
If end < startFrom (passed or calculated values), the method does nothing.

Example

 C_COLLECTION($c;$nc)

 $c:=New collection(1;2;3;4;5)

 $nc:=$c.slice(0;3) //$nc=[1,2,3]

 $nc:=$c.slice(3) //$nc=[4,5]

 $nc:=$c.slice(1;-1) //$nc=[2,3,4]

 $nc:=$c.slice(-3;-2) //$nc=[3]