Xsl how to avoid nan

Question

1.00/5 (1 vote)

See more:

I have several attributes which contain numbers. But one of them or several (or even every) may not be defined (i.e. no such attr in xml-file). I need to display sum of attrs, so when at least one of them is undefined I get NaN.

So how can I avoid getting NaN? I mean I need to interpret NaN value as 0, like NaN + 10 + 20 + NaN + 30 should give me 60 as result, but not NaN Is it any way to avoid NaN result without conditions, just like var||0 in JS will return 0 if var is undefined?

What I have tried:

Example of xml element. I need to sum every attr (attr3 is undefined)
<element attr1 = "5" attr2 = "1"/>

Example of xsl sum
<xsl:value-of select="@attr1 + @attr2 + @attr3"/>

Posted 27-Apr-16 10:00am

frostazaza

Updated 27-Apr-16 16:53pm

Add a Solution

Comments

Patrice T 27-Apr-16 16:05pm

Why don't you check if attributes exists ?

Sergey Alexandrovich Kryukov 27-Apr-16 17:42pm

The situation is actually much worse than that. I tried to describe it in my answer. :-)
—SA

3 solutions

Solution 1

No. Don't do it. NaN is not 0, 0 is not NaN. Pretending one is another would mean loss of data. Use NaN; this is a legitimate object you just fail to understand; it is very important.

I hope you understand that NaN is "not a number". By interpreting 0 as not a number, you put yourself in the position of ancient and early Medieval people who did not have zero or did not consider it as a number. Welcome back to the barbaric world!
(However, this roughly matches the level of understanding of mathematics and arithmetic by the U.S. Internal Revenue Service, people who collect taxes.
If you are one of them, your will probably need a century or two, to get to the world of mathematics a bit closer to the time of European Renaissance. :-))

Perhaps you need some understanding:
NaN — Wikipedia, the free encyclopedia[^],
Floating point — Wikipedia, the free encyclopedia[^],
IEEE floating point — Wikipedia, the free encyclopedia[^].

—SA

Posted 27-Apr-16 11:37am

Sergey Alexandrovich Kryukov

Updated 27-Apr-16 11:41am

v3

Comments

[no name] 28-Apr-16 16:02pm

5 also here

Sergey Alexandrovich Kryukov 28-Apr-16 17:06pm

Thank you.
—SA

Solution 3

I know this question already has an accepted answer, but it always makes me cringe when I see hard coded solutions like this.

Better to to try to sum up all existing attributes, than to use their specific names.
What if you want to add attr4 and attr5 later?
Then you have to change your code to work for that scenario.

The solution below only works if you want to get the sum of all existing attributes.

Example XML

XML

<root>
    <element attr1="10" attr2="20" />
    <element attr1="10" attr2="20" attr3="30" />
    <element attr1="10" attr2="20" attr3="30" attr4="40" attr5="50" />
</root>

XSLT

XML

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    xmlns:msxsl="urn:schemas-microsoft-com:xslt" exclude-result-prefixes="msxsl"
>
  <xsl:output method="text" indent="no" />

  <xsl:template match="root">
    <xsl:apply-templates select="element" />
  </xsl:template>

  <xsl:template match="element">
    Attribute Sum = <xsl:value-of select="sum(@*)" />
  </xsl:template>

</xsl:stylesheet>

Output

Attribute Sum = 30
Attribute Sum = 60
Attribute Sum = 150

Posted 27-Apr-16 16:53pm

George Jonsson

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

frostazaza · Accepted Answer · 2016-04-27T13:26:00

Solution 2

select="sum(@attr1 | @attr2 | @attr3)"

Posted 27-Apr-16 13:26pm

frostazaza