The IN function in xslt test boolean expression

can't find the answer anywhere whether you can do test="$var in ('Val1','Val2开发者_JS百科','Val3')" in XSLT instead of doing test="$var='Val1' or $var='Val2' or $var='Val3'"?

---

In XSLT 1.0, you can use the contains() function:

test(contains('Val1,Val2,Val3',$var))`

It returns a boolean result, testing whether the first string contains the second string.

A common way to help reduce false-positive results for partial string matches is to use a delimiter and pad the values with that delimiter:

test="contains(' Val1 Val2 Val3 ', concat(' ',$var,' '))

That way, if the value of $var was "Val", it would only return true if "Val" were added to the list of values being tested.

In XSLT 2.0, you could use:

test="$var = ('Val1','Val2','Val3')"

It will return true if $var is equal to any of the items in the sequence (which is what you define when you have a comma separated list of values inside of parenthesis).

Another XSLT 2.0 solution:

test="some $value in ('Val1','Val2','Val3') satisfies $var=$value"

---

I. XPath 1.0 / XSLT 1.0

Use:

contains(concat($Sep, 'Val1', $Sep, 'Val2', $Sep, 'Val3', $Sep),
         concat($Sep, $var, $Sep)
        )

where $Sep is a string that is guaranteed not to appear in any of the values.

The concatenation is nesessary to exclude false positives when one or more of the values start-with or end-with the value of $var.

The comparison is even easier if 'Val1', 'Val2' and 'Val3' are text nodes (say of /a/b):

$var = /a/b

II. XPath 2.0 (XSLT 2.0)

$var = ('Val1', 'Val2', 'Val3')

---

XSLT/XPath doesn't have support for IN expressions.

But you can to store those values into an XML fragment and search inside it.