XPath test if node value is number

Question

How can I check if a node value is a number using XPath   Any ideas

User · Answer

You could always use something like this   string   Sesscode  castable as xs decimal   castable is documented by W3C here

User · Answer

The one I found very useful is the following    lt xsl choose gt     lt xsl when test  not number myNode    gt         lt  -- myNode is a not a number or empty NaN  or zero -- gt           lt  xsl when gt     lt xsl otherwise gt         lt  -- myNode is a number     zero  -- gt             lt  xsl otherwise gt   lt  xsl choose gt

User · Answer

The shortest possible way to test if the value contained in a variable  v can be used as a number is   number  v    number  v    You only need to substitute the  v above with the expression whose value you want to test   Explanation   number  v    number  v  is obviously true  if  v is a number  or a string that represents a number   It is true also for a boolean value  because a number true    is 1 and number false  is 0   Whenever  v cannot be used as a number  then number  v  is NaN  and NaN is not equal to any other value  even to itself   Thus  the above expression is true only for  v whose value can be used as a number  and false otherwise

User · Answer

There s an amazing type test operator in XPath 2 0 you can use     lt xsl if test   number castable as xs double  gt       lt  -- implementation -- gt   lt  xsl if gt

User · Answer

I ve been dealing with 01 - which is a numeric   string number  v      string  v  makes the segregation

User · Answer

I m not trying to provide a yet another alternative solution  but a  meta view  to this problem    Answers already provided by Oded and Dimitre Novatchev are correct but what people really might mean with phrase  value is a number  is  how would I say it  open to interpretation   In a way it all comes to this bizarre sounding question   how do you want to express your numeric values    XPath function number   processes numbers that have   possible leading or trailing whitespace preceding sign character only on negative values dot as an decimal separator  optional for integers  all other characters from range  0-9    Note that this doesn t include expressions for numerical values that   are expressed in exponential form  e g  12 3E45  may contain sign character for positive values have a distinction between positive and negative zero include value for positive or negative infinity   These are not just made up criteria  An element with content that is according to schema a valid xs float value might contain any of the above mentioned characteristics  Yet number   would return value NaN   So answer to your question  How i can check with XPath if a node value is number   is either  Use already mentioned solutions using number    or  with a single XPath 1 0 expression  you can t   Think about the possible number formats you might encounter  and if needed  write some kind of logic for validation number parsing  Within XSLT processing  this can be done with few suitable extra templates  for example   PS  If you only care about non-zero numbers  the shortest test is   lt xsl if test  number myNode   gt       lt  -- myNode is a non-zero number -- gt   lt  xsl if gt

User · Answer

Test the value against NaN    lt xsl if test  string number myNode       NaN   gt       lt  -- myNode is a number -- gt   lt  xsl if gt    This is a shorter version  thanks  Alejandro     lt xsl if test  number myNode    myNode  gt       lt  -- myNode is a number -- gt   lt  xsl if gt

[xpath] XPath test if node value is number

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