XSl:Variable - Condition to check whether value exist - xslt

Using XSLT 1.0, how do I check whether the value in the variable exists or not?
I am assigning the value to the variable initially from my XML data and then need to check whether it exits or not:
<xsl:variable name="DOC_TYPE">
<xsl:value-of select="name(./RootTag/*[1])"/>
</xsl:variable>
<xsl:if test="string($DOC_TYPE) = ''">
<xsl:variable name="DOC_TYPE">
<xsl:value-of select="name(./*[1])"/>
</xsl:variable>
</xsl:if>
The above is not working as expected. What I need is if <RootTag> exists in my data then the variable should contain the child node below the <RootTag>. If <RootTag> does not exist then the DOC_TYPE should be the first Tag in my XML data.
Thanks for your response.

You can't re-assign variables in XSLT. Variables a immutable, you can't change their value. Ever.
This means you must decide within the variable declaration what value it is going to have:
<xsl:variable name="DOC_TYPE">
<xsl:choose>
<xsl:when test="RootTag">
<xsl:value-of select="name(RootTag/*[1])" />
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="name(*[1])" />
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
A few other notes:
this: './RootTag' is redundant. Every XPath you don't start with a slash is relative by default, so saying 'RootTag' is enough
this: <xsl:value-of select="name(*[1])"/> already results in a string (names are strings by definition), so there is no need to do <xsl:if test="string($DOC_TYPE) = ''"> , a simple <xsl:if test="$DOC_TYPE = ''"> suffices
to check if a node exists simply select it via XPath in a test="..." expression - any non-empty node-set evaluates to true
XSLT has strict scoping rules. Variables are valid within their parent elements only. Your second variable (the one within the <xsl:if>) would go out of scope immediately(meaning right at the </xsl:if>).

Try this
<xsl:variable name="DOC_TYPE">
<xsl:choose>
<xsl:when test="/RootTag"><xsl:value-of select="name(/RootTag/*[1])"></xsl:value-of></xsl:when>
<xsl:otherwise><xsl:value-of select="name(/*[1])"/></xsl:otherwise>
</xsl:choose>
</xsl:variable>

It only exists if you have assigned it. There's no reason to test it for existence.
See also here

Related

Setting a value in a variable on if conditions using XSL

I have a basic condition that checks if a variable is empty and if it is set the variable to a specific value like so.
<xsl:variable name="PIC" select="avatar"/>
<xsl:choose>
<xsl:when test="avatar !=''">
<xsl:variable name="PIC" select="avatar"/>
</xsl:when>
<xsl:otherwise>
<xsl:variable name="PIC" select="'placeholder.jpg'"/>
</xsl:otherwise>
</xsl:choose>
Basically var PIC is set to whatever avatar returns. Then a test is carried to check if if it's not empty and assigned to var PIC and if it is empty a value placeholder.jpg is added to var PIC instead.
Now for some reason I keep getting the following warning
A variable with no following sibling instructions has no effect
Any ideas on what I am doing wrong here?
Variables are immutable in XSLT, and cannot be changed once set. The variable declarations in the xsl:choose are simply new declarations that at local in scope to the current block. (They are said to "shadow" the initial variable).
What you need to do is this...
<xsl:variable name="PIC">
<xsl:choose>
<xsl:when test="avatar !=''">
<xsl:value-of select="avatar"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="'placeholder.jpg'"/>
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
Use a single xsl:variable as <xsl:variable name="PIC" select="if (avatar != '') then avatar else 'placeholder.jpg'"/>.

How to get value of a child of node-set?

I am using a variable in my XSLT to select correct node and then I want to use this variable to retrieve its child nodes:
<xsl:variable name="CorrectNode">
<xsl:choose>
<xsl:when test="$Formula='14'">
<xsl:value-of select="f:node14" />
</xsl:when>
<xsl:when test="$Formula='15'">
<xsl:value-of select="f:node15" />
</xsl:when>
</xsl:choose>
</xsl:variable>
<Revenue>
<xsl:value-of select="msxsl:node-set($CorrectNode)/f1:revenueValue" />
</Revenue>
However, it does not output anything. If I have:
<xsl:value-of select="msxsl:node-set($CorrectNode)" />
or
<xsl:copy-of select="msxsl:node-set($CorrectNode)" />
then the values or nodes are outputted but how to access its children?
This snippet sets the variable to a result tree fragment consisting of one text node, whose value is the string value of the appropriate element. The variable does not refer to the element itself, only its string value.
But you don't need the RTF and node-set function here at all, as you can do it with a straight select using appropriate predicates, since the test expressions are not context-dependent (a test like $Formula = '15' gives the same value regardless of whether the current context is the f:node15 element or its parent):
<xsl:variable name="CorrectNode"
select="f:node14[$Formula = '14'] | f:node15[$Formula = '15']" />
This way the variable is a reference to the original element, and you can navigate from there using XPath.

Accessing a variable outside the for loop in xsl

I am setting a variable as shown below..
<xsl:variable name="FoundFloating"> <xsl:value-of select="'no'" />
</xsl:variable>
Now I am doing some processing as shown below ..
<xsl:if test="$abcid=$def_id">
<xsl:for-each "$abcd">
<xsl:variable name="abcRate"> <xsl:value-of select="./def_Period/"/>
</xsl:variable>
<xsl:choose>
<xsl:when test="$abcdf !=$abcRate">
<xsl:variable name="$FoundFloating"> <xsl:value-of select="yes" />
</xsl:variable>
</xsl:when>
</xsl:choose>
</xsl:for-each>
Now after this xsl for I am evaluating as shown below.. But my query is that whether foundfloating variable is accessible as the for loop is already ended..
<xsl:choose>
<xsl:when test="$FoundFloating='yes'"> <xsl:value-of select="'AAA'" />
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="'BBBA'" />
</xsl:otherwise>
</xsl:choose>
Now after this xsl for I am evaluating as shown below.. But my query is that whether foundfloating variable is accessible as the for loop is already ended..
Please advise on this as I have updated the post
The first thing to note is that variables are immutable in XSLT. This means once declared, they cannot be changed. What is actually happening in your XSLT sample is you are declaring a whole new variable, with the same name.
The FoundFloating variable you are declaring within the for loop will not be accessible outside the for loop, as it will only be local in scope. In fact, it will only be accessible inside the xsl:when statement it is defined in. It is a different variable to the global one you defined, and only exists in the loop.
You don't really need the loop here. You can combine the condition in the xsl:for-each and the condition in the xsl:when into a single variable declaration.
<xsl:if test="$abcid=$def_id">
<xsl:variable name="FoundFloating">
<xsl:if test="$abcd[def_Period != $abcdf]">yes</xsl:if>
</xsl:variable>
<xsl:choose>
<xsl:when test="$FoundFloating='yes'">
(This replaces the xsl:for-each statement entirely)
In fact, this can be simplified even more, by simply setting FoundFloating to the node itself (if there is one), rather than "yes"
<xsl:if test="$abcid=$def_id">
<xsl:variable name="FoundFloating" select="$abcd[def_Period != $abcdf]" />
<xsl:choose>
<xsl:when test="$FoundFloating">
This works because the essence of the test is whether a certain node exists matching the condition. Rather than setting a variable to "Yes" or "No" if it exists or not, the variable is set to the node itself. Then, if it does the exist the statement <xsl:when test="$FoundFloating"> returns true, but false if it doesn't.
So, you don't need the xsl:for-each loop, and you only need to declare the FoundFloating variable once.

xslt assigning variable value to string literal

I have
<xsl:for-each select="ancestor-or-self::*">
<xsl:variable name="expression" select="name()" ></xsl:variable>
</xsl:for-each>
below I have href and i want to set the value this expression variable in href #######
Delete
I also tried with :
Delete
None of them worked.
Can Anybody help me out how to do that?
Basically my task is to find the expression for current node and send the expression for the same in href?
Adding More Info :
<br/><xsl:for-each select="ancestor-or-self::*">
<xsl:variable name="expression" select="name()" />
</xsl:for-each>
<b>Click Me</b>
when above xsl code is transformed it is giving below error:
Variable or parameter 'expression' is undefined.
In XSLT1.0, you could try setting the variable like so:
<xsl:variable name="expression">
<xsl:for-each select="ancestor-or-self::*">
<xsl:text>/</xsl:text>
<xsl:variable name="name" select="name()"/>
<xsl:value-of select="$name"/>
</xsl:for-each>
</xsl:variable>
So, assuming the following XML structure
<As>
<a>
<Bs>
<b>5</b>
</Bs>
</a>
<a>
<Bs>
<b>9</b>
</Bs>
</a>
<a/>
<a>
<Bs>
<b>12</b>
<b>14</b>
<b>15</b>
</Bs>
</a>
</As>
If you were positioned on the b element with the value of 14, then expression would be set to /As/a/Bs/b
However, this does not take into account multiple nodes with the same name, and so would not be sufficient if you wanted accurate XPath to select the node.
Instead, you could try the following:
<xsl:variable name="expression">
<xsl:for-each select="ancestor-or-self::*">
<xsl:text>/</xsl:text>
<xsl:variable name="name" select="name()"/>
<xsl:value-of select="$name"/>
<xsl:text>[</xsl:text>
<xsl:value-of select="count(preceding-sibling::*[name() = $name]) + 1"/>
<xsl:text>]</xsl:text>
</xsl:for-each>
</xsl:variable>
This would return /As[1]/a[4]/Bs[1]/b[2], which may be what you want.
Very simply, variables are scoped in XSL and exist only within the containing tag. Thus the variable named expression exists only within the for-each block. Also, variables can only be set once. Attempting to set a variable value a second time has no effect.
Therfore you have to declare the variable at or above the level where you want to use it, and put all the code to generate the value inside the variable declaration. If you can use XSLT2, the following will do what you want:
string-join(for $n in ancestor-or-self::* return name($n), '/')
I know it can also be done in XSLT 1 with a recursive template, but I don't have an example handy.

XSLT:How to deal with testing the value of an element?

I have an xml file in which there is tag namely, <Gender/> It carries either 'M' or 'F' as data, now my work is to test the value and write <Gender_Tag>Male</Gender_Tag> or <Gender_Tag>Female</Gender_Tag> according to the values M or F respectively .. I tried this code .. It used to work in other circumstances..
All relative paths expressed in a template are evaluated against the current node. Your template match Gender elements, so Gender='M' returns true if there is any Gender's child named 'Gender' with the value 'M'. I guess this is not the case...
Use the dot to express the current node (here a Gender element):
<xsl:template match="root/details/Gender">
<Gender_Tag>
<xsl:choose>
<xsl:when test=".='M'">
<xsl:text>Male</xsl:text>
</xsl:when>
<xsl:otherwise>
<xsl:text>Female</xsl:text>
</xsl:otherwise>
</xsl:choose>
</Gender_Tag>
</xsl:template>
EDIT: You may use two templates too
<xsl:template match="root/details/Gender[.='M']">
<Gender_Tag>Male</Gender_Tag>
</xsl:template>
<xsl:template match="root/details/Gender[.='F']">
<Gender_Tag>Female</Gender_Tag>
</xsl:template>
<xsl:template match="root/details/Gender">
<xsl:choose>
<xsl:when test="normalize-space(text())='M'">
<Gender_Tag>Male</Gender_Tag>
</xsl:when>
<xsl:otherwise>
<Gender_Tag>Female</Gender_Tag>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
My example differs in two points from Scoregraphic's:
It uses xsl:choose to ensure, that only one Gender_Tag element is created (that also means, that if the text is not 'M', it is always a Female)
Use of normalize-space() strips white space around the text content of the element.
Untested, but may work...
<xsl:template match="root/details/Gender">
<xsl:if test="text()='M'">
<Gender_Tag>Male</Gender_Tag>
</xsl:if>
<xsl:if test="text()='F'">
<Gender_Tag>Female</Gender_Tag>
</xsl:if>
</xsl:template>
Without seeing XML its hard to be certain, but I think your sample XSLT should be:
<xsl:template match="root/details/Gender">
<xsl:if test=".='M'">
<Gender_Tag><xsl:text>Male</xsl:text></Gender_Tag>
</xsl:if>
<xsl:if test=".='F'">
<Gender_Tag><xsl:text>Female</xsl:text></Gender_Tag>
</xsl:if>
</xsl:template>
Use of choose as per another answer would be better (though I think it should be two explicit when clauses rather than a when and an otherwise)