Function that can be use to omit duplicate value on a string

Question

I would like to ask if there is a function that can be use to to remove a duplicate value inside a string separated by | simplest possible way. I have below example of the s

Answer 1

All presented XSLT 1.0 solutions so far produce the wrong result:

1111-1|1111-4|1111-5|1111-3

whereas the wanted, correct result is:

1111-1|1111-3|1111-4|1111-5

Now, the following transformation (no extensions, pure XSLT 1.0):

when applied on this XML document (with string value the provided string in the question):

1111-1|1111-1|1111-3|1111-4|1111-5|1111-3

produces the wanted, correct result:

1111-1|1111-3|1111-4|1111-5

Explanation:

1. All found distinct substrings are concatenated in the parameter $pFoundDistinctSubs -- whenever we get the next substring from the delimited input, we compare it to the distinct substrings passed in this parameter. This ensures that the first in order distinct substring will be output -- not the last as in the other two solutions.

2. We use conditionless value determination, based on the fact that XSLT 1.0 implicitly converts a Boolean false() to 0 and true() to 1 whenever it is used in a context that requires a numeric value. In particular, substring($x, 1 div true()) is equivalent to substring($x, 1 div 1) that is: substring($x, 1) and this is the entire string $x. On the other side, substring($x, 1 div false()) is equivalent to substring($x, 1 div 0) -- that is: substring($x, Infinity) and this is the empty string.

To know why avoiding conditionals is important: watch this Pluralsight course:

Tactical Design Patterns in .NET: Control Flow, by Zoran Horvat