PML Customisation
User Guide
Arrays : Sorting Arrays using the VAR Command
Where a multi-level sort is required it is still necessary to use the older facilities of the VAR command to perform the sort. Using a different example, look at the arrays !Car, !Colour and !Year:
The sorted index values are put into the array !Index, (for clarity shown here with the rows of the original arrays they are pointing to),
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Sorts in ascending case-independent alphabetic order.
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Sorts in alphabetic in reverse order
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Sorts in descending case-independent alphabetic order.
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Forces an ascending numerical sort on numbers held as strings.
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Forces a descending numerical sort on numbers held as strings.
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!Index would then have only 9 elements as the value in the original row 10 was a second reference to a 1993 yellow Ford which is discarded.
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Eliminates rows that contain only UNSET values.
Again !Index would have only 9 elements as the original row 8 is discarded.
The option NOEMPTY discards rows with values that are all blanks.
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To sort these arrays and identify the last occurrence of each group of the same car type, use the LASTINGROUP option:
This would create !Index by sorting the values in the array !Car , but would also would also create the array !Last:
A similar option FIRSTINGROUP identifies the first row of each group.
