Caché ObjectScript Reference - InterSystems Documentation

See Also• $ZWIDTH function$ZPREVIOUS$ZPREVIOUSReturns the previous array node subscript for the specified variable.$ZPREVIOUS(variable)$ZP(variable)ParametervariableName of local or global array variable or the null string. It can be specifiedas a value, a variable, or an expression.Description$ZPREVIOUS returns the previous array node subscript for the specified variable.$ZPREVIOUS is similar to the $ORDER function, except that it returns the previous, ratherthat the next, subscript in the collation sequence.You can use it to traverse a global in reverse subscript order. To start at the last subscript ona given level, specify the null string for the subscript reference. $ZPREVIOUS returns thenull string after it returns the first subscript on the root level.As with $ORDER, you can use $ZPREVIOUS on both local and global variables.Use of $ZPREVIOUS is discouraged. Rather, use the form $ORDER(variable,-1).ExampleGiven the array node definitions shown, and starting with the last subscript, $ZPREVIOUSreturns the following results:SET ^ABC(1)=1SET ^ABC(2)=2SET ^ABC(3)=3SET x=$ZPREVIOUS(^ABC("")) ; 3WRITE !,"Third is ",xSET x=$ZPREVIOUS(^ABC(x)) ; 2WRITE !,"Second is ",xSET x=$ZPREVIOUS(^ABC(x)) ; 1WRITE !,"First is ",xSET x=$ZPREVIOUS(^ABC(x)) ; ""WRITE !,"Top is ",xCaché ObjectScript Reference 555