Xpath for selecting html id including random number

Question

Hi how would I select all link when they have the following id.

<a id="List_ctl01_link3" class="content" href=link1.aspx">
<a id="List_ctl02_link3" class="content" href=link2.aspx">
<a id="List_ctl03_link3" class="content" href=link3.aspx">
<a id="List_ctl04_link3" class="content" href=link4.aspx">

And so on...

Please note that the last part "link3" is important, and must be included in the Xpath.

I'm using C# and Html agility pack.

Good question, +1. See my answer for the most precise solution so far. :) — Dimitre Novatchev, Nov 11 '10 at 05:55

score 5 · Answer 1 · answered Nov 10 '10 at 15:11

Hi how would I select all link when they have the following id

Use this XPath expression:

//a[@id[starts-with(.,'List_ctl')][substring(.,string-length()-5)='_link3']]

Note: There is no fn:ends-with() in XPath 1.0. Use last predicate instead.

score 3 · Answer 2 · answered Nov 11 '10 at 03:51

Use:

//a[@id[starts-with(.,'List_ctl')
      and
        substring(.,string-length()-5)='_link3'
      and
         floor(substring-before(substring_after(.,'List_ctl'),'_'))
        =
         floor(substring-before(substring_after(.,'List_ctl'),'_'))
       ]
   ]

This XPath expression selects all a elements in the document whose id attribute has string value with all of the following properties:

Starts with the string 'List_ctl' .
Ends with the string '_link3' .
The substring surrounded by 'List_ctl' and '_' is a representation of an integer.

score 2 · Accepted Answer · answered Nov 10 '10 at 08:55

2

In case you use xpath 2.0 you can try match/matches functions and use regular expressions. If you are with xpath 1.0 probably you will have to write your custom attribute parser (take a look at xsl:function). AFAIR the match function is available only xpath 2.0.

Probably @id[starts-with(., 'List_ct') and ends-with(., 'link3')] is another way to do it.

answered Nov 10 '10 at 08:55

Alex Nikolaenkov

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Thx, I used the starts-with solution and it works perfectly :-) – gulbaek Nov 10 '10 at 09:56
Do note that there is no `fn:ends-with()` in XPath 1.0 – Nov 10 '10 at 15:11
@Alejandro, thanks. I've assumed that if there is fn:starts-with() in xpath 1.0 there should be fn:ends-with() for consistency reasons. Me bad. Had to check that. – Alex Nikolaenkov Nov 11 '10 at 05:58

Xpath for selecting html id including random number

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