Find position of a node using xpath

Question

Anyone know how to get the position of a node using xpath   Say I have the following xml    lt a gt       lt b gt zyx lt  b gt       lt b gt wvu lt  b gt       lt b gt tsr lt  b gt       lt b gt qpo lt  b gt   lt  a gt    I can use the following xpath query to select the third  lt b gt  node   lt b gt tsr lt  b gt     a b    tsr     Which is all well and good but I want to return the ordinal position of that node  something like   a b    tsr   position      but a bit more working    Is it even possible   edit  Forgot to mention am using  net 2 so it s xpath 1 0     Update  Ended up using James Sulak s excellent answer  For those that are interested here s my implementation in C    int position   doc SelectNodes  a b    tsr   preceding-sibling  b   Count   1      Check the node actually exists if  position  gt  1    doc SelectSingleNode  a b    tsr        null        Console WriteLine  Found at position    0    position

User · Answer

Unlike stated previously  preceding-sibling  is really the axis to use  not  preceding  which does something completely different  it selects everything in the document that is before the start tag of the current node   see http   www w3schools com xpath xpath axes asp

User · Answer

Just a note to the answer done by James Sulak   If you want to take into consideration that the node may not exist and want to keep it purely XPATH  then try the following that will return 0 if the node does not exist   count a b    tsr   preceding-sibling     number boolean a b    tsr

User · Answer

The problem is that the position of the node doesn t mean much without a context   The following code will give you the location of the node in its parent child nodes  using System  using System Xml   public class XpathFinder       public static void Main string   args                XmlDocument xmldoc   new XmlDocument            xmldoc Load args 0            foreach   XmlNode xn in xmldoc SelectNodes args 1                           for  int i   0  i  lt  xn ParentNode ChildNodes Count  i                                  if   xn ParentNode ChildNodes i  Equals  xn                                           Console Out WriteLine  i                        break

User · Answer

If you ever upgrade to XPath 2 0  note that it provides function index-of  it solves problem this way   index-of   b    b    tsr      Where    1st parameter is sequence for searching 2nd is what to search

User · Answer

I do a lot of Novell Identity Manager stuff  and XPATH in that context looks a little different   Assume the value you are looking for is in a string variable  called TARGET  then the XPATH would be   count attr value     TARGET   preceding-sibling     1   Additionally it was pointed out that to save a few characters of space  the following would work as well   count attr value     TARGET   preceding       1   I also posted a prettier version of this at Novell s Cool Solutions  Using XPATH to get the position node

User · Answer

I do a lot of Novell Identity Manager stuff  and XPATH in that context looks a little different   Assume the value you are looking for is in a string variable  called TARGET  then the XPATH would be   count attr value     TARGET   preceding-sibling     1   Additionally it was pointed out that to save a few characters of space  the following would work as well   count attr value     TARGET   preceding       1   I also posted a prettier version of this at Novell s Cool Solutions  Using XPATH to get the position node

User · Answer

You can do this with XSLT but I m not sure about straight XPath    lt  xml version  1 0  encoding  UTF-8  standalone  yes   gt   lt xsl stylesheet version  1 0  xmlns xsl  http   www w3 org 1999 XSL Transform  gt     lt xsl output method  xml  encoding  utf-8  indent  yes                 omit-xml-declaration  yes   gt     lt xsl template match  a   text    tsr    gt       lt xsl number value-of  position     gt     lt  xsl template gt     lt xsl template match  text     gt   lt  xsl stylesheet gt

User · Answer

The problem is that the position of the node doesn t mean much without a context   The following code will give you the location of the node in its parent child nodes  using System  using System Xml   public class XpathFinder       public static void Main string   args                XmlDocument xmldoc   new XmlDocument            xmldoc Load args 0            foreach   XmlNode xn in xmldoc SelectNodes args 1                           for  int i   0  i  lt  xn ParentNode ChildNodes Count  i                                  if   xn ParentNode ChildNodes i  Equals  xn                                           Console Out WriteLine  i                        break

User · Answer

Try   count a b    tsr   preceding-sibling     1

User · Answer

The problem is that the position of the node doesn t mean much without a context   The following code will give you the location of the node in its parent child nodes  using System  using System Xml   public class XpathFinder       public static void Main string   args                XmlDocument xmldoc   new XmlDocument            xmldoc Load args 0            foreach   XmlNode xn in xmldoc SelectNodes args 1                           for  int i   0  i  lt  xn ParentNode ChildNodes Count  i                                  if   xn ParentNode ChildNodes i  Equals  xn                                           Console Out WriteLine  i                        break

User · Answer

Try   count a b    tsr   preceding-sibling     1

User · Answer

You can do this with XSLT but I m not sure about straight XPath    lt  xml version  1 0  encoding  UTF-8  standalone  yes   gt   lt xsl stylesheet version  1 0  xmlns xsl  http   www w3 org 1999 XSL Transform  gt     lt xsl output method  xml  encoding  utf-8  indent  yes                 omit-xml-declaration  yes   gt     lt xsl template match  a   text    tsr    gt       lt xsl number value-of  position     gt     lt  xsl template gt     lt xsl template match  text     gt   lt  xsl stylesheet gt

User · Answer

Try   count a b    tsr   preceding-sibling     1

User · Answer

Just a note to the answer done by James Sulak   If you want to take into consideration that the node may not exist and want to keep it purely XPATH  then try the following that will return 0 if the node does not exist   count a b    tsr   preceding-sibling     number boolean a b    tsr

User · Answer

Try   count a b    tsr   preceding-sibling     1

User · Answer

I do a lot of Novell Identity Manager stuff  and XPATH in that context looks a little different   Assume the value you are looking for is in a string variable  called TARGET  then the XPATH would be   count attr value     TARGET   preceding-sibling     1   Additionally it was pointed out that to save a few characters of space  the following would work as well   count attr value     TARGET   preceding       1   I also posted a prettier version of this at Novell s Cool Solutions  Using XPATH to get the position node

User · Answer

You can do this with XSLT but I m not sure about straight XPath    lt  xml version  1 0  encoding  UTF-8  standalone  yes   gt   lt xsl stylesheet version  1 0  xmlns xsl  http   www w3 org 1999 XSL Transform  gt     lt xsl output method  xml  encoding  utf-8  indent  yes                 omit-xml-declaration  yes   gt     lt xsl template match  a   text    tsr    gt       lt xsl number value-of  position     gt     lt  xsl template gt     lt xsl template match  text     gt   lt  xsl stylesheet gt

User · Answer

I realize that the post is ancient   but    replace ing the asterisk with the nodename would give you better results  count a b    tsr   preceding  a  1    instead of  count a b    tsr   preceding     1

User · Answer

If you ever upgrade to XPath 2 0  note that it provides function index-of  it solves problem this way   index-of   b    b    tsr      Where    1st parameter is sequence for searching 2nd is what to search

User · Answer

I do a lot of Novell Identity Manager stuff  and XPATH in that context looks a little different   Assume the value you are looking for is in a string variable  called TARGET  then the XPATH would be   count attr value     TARGET   preceding-sibling     1   Additionally it was pointed out that to save a few characters of space  the following would work as well   count attr value     TARGET   preceding       1   I also posted a prettier version of this at Novell s Cool Solutions  Using XPATH to get the position node

User · Answer

You can do this with XSLT but I m not sure about straight XPath    lt  xml version  1 0  encoding  UTF-8  standalone  yes   gt   lt xsl stylesheet version  1 0  xmlns xsl  http   www w3 org 1999 XSL Transform  gt     lt xsl output method  xml  encoding  utf-8  indent  yes                 omit-xml-declaration  yes   gt     lt xsl template match  a   text    tsr    gt       lt xsl number value-of  position     gt     lt  xsl template gt     lt xsl template match  text     gt   lt  xsl stylesheet gt

User · Answer

I realize that the post is ancient   but    replace ing the asterisk with the nodename would give you better results  count a b    tsr   preceding  a  1    instead of  count a b    tsr   preceding     1

User · Answer

The problem is that the position of the node doesn t mean much without a context   The following code will give you the location of the node in its parent child nodes  using System  using System Xml   public class XpathFinder       public static void Main string   args                XmlDocument xmldoc   new XmlDocument            xmldoc Load args 0            foreach   XmlNode xn in xmldoc SelectNodes args 1                           for  int i   0  i  lt  xn ParentNode ChildNodes Count  i                                  if   xn ParentNode ChildNodes i  Equals  xn                                           Console Out WriteLine  i                        break

User · Answer

Unlike stated previously  preceding-sibling  is really the axis to use  not  preceding  which does something completely different  it selects everything in the document that is before the start tag of the current node   see http   www w3schools com xpath xpath axes asp

[xpath] Find position of a node using xpath

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