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xPath queryI'm trying the select a element based on values of two attributes. In the
Xml doc i need to look at an attribute minVal and maxVal. if the Value I'm passing in in the xPath is greate than min "and" less than max, I'll want to pull all the attributes of that element. Is this possible with xPath? I'm able to easily query 1 attribute, but not two. Thanks TR TR wrote:
> I'm trying the select a element based on values of two attributes. In //element[$value > @minValue and $value < @maxValue]/@*> the Xml doc i need to look at an attribute minVal and maxVal. if the > Value I'm passing in in the xPath is greate than min "and" less than > max, I'll want to pull all the attributes of that element. Hello Martin,
Thanks for the reply. I forget to mention 1 thing. I values need to be greater-than or equal to and less-than or equal to. I missed the equal to part. the syntax you provided worked for evaluating two the attributes. Tr Show quote > TR wrote: > >> I'm trying the select a element based on values of two attributes. >> In the Xml doc i need to look at an attribute minVal and maxVal. if >> the Value I'm passing in in the xPath is greate than min "and" less >> than max, I'll want to pull all the attributes of that element. >> > //element[$value > @minValue and $value < @maxValue]/@* > Hi TR,
XPath supports the operators >= and <= as well. You can use these in the expression that Martin provided to meet your requirement. //element[$value >= @minValue and $value <= @maxValue]/@* HTH, Regards, Cerebrus. Hello Cerebrus,
Thanks for the follow-up. here are some details and results.... Below is a snippet of the Xml I'm trying to select. If a match is found, I need to use all attribs of the Node <Node> <Formgroups> <Formula MinAmt="0" MaxAmt="51" Group="0" PercentValue="0"> </Formula> <Formula MinAmt="51" MaxAmt="192" Group="51.00" PercentValue="10"> </Formula> <Formula MinAmt="192" MaxAmt="620" Group="98.00" PercentValue="15"> </Formula> <Formula MinAmt="620" MaxAmt="1409" Group="306.80" PercentValue="25"> </Formula> </Formgroups> </Node> EX:: $Value=53 Result: NodeList.item(0) should be: <Formula MinAmt="51" MaxAmt="192" Group="51.00" PercentValue="10"> </Formula> Current syntax /Node/Formgroups/Formula[@MinAmt >= $Value] == Works /Node/Formgroups/Formula[@MinAmt >= $Value and(@MaxAmt <= $Value)] === Fails /Node/Formgroups/Formula[@MinAmt >= $Value and @MaxAmt <= $Value] ===Fails Also, I tried the syntax you include at the end of the attribute eval, " /@* ". Not sure what that does, but I put it in and still no luck. The xPath expression was valid, just nothing populated in my NodeList Thanks again!!! Appreciate the assistance. Show quote > Hi TR, > > XPath supports the operators >= and <= as well. You can use these in > the expression that Martin provided to meet your requirement. > > //element[$value >= @minValue and $value <= @maxValue]/@* > > HTH, > > Regards, > > Cerebrus. > TR wrote:
Show quote > Below is a snippet of the Xml I'm trying to select. If a match is found, Here is one example> I need to use all attribs of the Node > > <Node> > <Formgroups> > <Formula MinAmt="0" MaxAmt="51" Group="0" PercentValue="0"> </Formula> > <Formula MinAmt="51" MaxAmt="192" Group="51.00" PercentValue="10"> > </Formula> > <Formula MinAmt="192" MaxAmt="620" Group="98.00" PercentValue="15"> > </Formula> > <Formula MinAmt="620" MaxAmt="1409" Group="306.80" > PercentValue="25"> </Formula> > </Formgroups> > </Node> public static void Test (double value, string url) { XPathDocument xmlDocument = new XPathDocument(url); string xPathExpression = String.Format( CultureInfo.InvariantCulture, "Node/Formgroups/Formula[{0} >= @MinAmt and {0} <= @MaxAmt]", value ); XPathNavigator xPathNavigator = xmlDocument.CreateNavigator(); XPathNodeIterator nodeIterator = xPathNavigator.Select(xPathExpression); while (nodeIterator.MoveNext()) { Console.WriteLine("Found {0}, attributes are:", nodeIterator.Current.Name); if (nodeIterator.Current.MoveToFirstAttribute()) { do { Console.WriteLine("Attribute name: {0}, attribute value: {1}", nodeIterator.Current.Name, nodeIterator.Current.Value); } while (nodeIterator.Current.MoveToNextAttribute()); nodeIterator.Current.MoveToParent(); } Console.WriteLine(); } } you could call that as e.g. Test(53.6, @"example.xml"); and then the output is Found Formula, attributes are: Attribute name: MinAmt, attribute value: 51 Attribute name: MaxAmt, attribute value: 192 Attribute name: Group, attribute value: 51.00 Attribute name: PercentValue, attribute value: 10 Hi TR,
1. The " /@* " at the end selects all the attributes of all the returned nodes. Martin probably added that in because of your original statement : "I'll want to pull all the attributes of that element." 2. Well, I don't know if we're on the same page, but in your example : (Using sample $Value of 53 on your sample XML) As expected, only the first one of your 3 XPath expressions will work. Reasons are below... The first expression selects the 3rd and 4th node. The second and 3rd expression won't select anything. This is because you're making a logical mistake here. The 3rd expression should be : /Node/Formgroups/Formula[@MinAmt >= $Value and $Value <= @MaxAmt]. ^^^^^^^^^ This is because you need to select a value that is greater than the MinAmt and *less than* the MaxAmt. The expression you've written can be interpreted as MaxAmt <= Value <= MinAmt, which is impossible in your XML file. So, it does not select anything. When written properly, your XPath should select the 3rd and 4th node. (of the sample XML you gave) Hope this helps, Regards, Cerebrus. Hi TR,
1. The " /@* " at the end selects all the attributes of all the returned nodes. Martin probably added that in because of your original statement : "I'll want to pull all the attributes of that element." 2. Well, I don't know if we're on the same page, but in your example : (Using sample $Value of 53 on your sample XML) As expected, only the first one of your 3 XPath expressions will work. Reasons are below... The first expression selects the 3rd and 4th node. The second and 3rd expression won't select anything. This is because you're making a logical mistake here. The 3rd expression should be : /Node/Formgroups/Formula[@MinAmt >= $Value and $Value <= @MaxAmt]. This is because you need to select a value that is greater than the MinAmt and *less than* the MaxAmt. The expression you've written can be interpreted as MaxAmt <= Value <= MinAmt, which is impossible in your XML file. So, it does not select anything. When written properly, your XPath should select the 3rd and 4th node. (of the sample XML you gave) , Edit: And not the 2nd node. Hope this helps, Regards, Cerebrus. Hello Cerebrus, Martin,
I appreciate the assistance. The syntax provided partially works. You made it very clear on the logic error. I tried the syntax provided, but something still doen't work correctly. If I provide a value of say, 195, the expression returns record 4 from the example previously. It should have returned records 3 and 4. Thanks!!!! TR Show quote > Hi TR, > > 1. The " /@* " at the end selects all the attributes of all the > returned nodes. Martin probably added that in because of your original > statement : "I'll want to pull all the attributes of that element." > > 2. Well, I don't know if we're on the same page, but in your example : > (Using sample $Value of 53 on your sample XML) > > As expected, only the first one of your 3 XPath expressions will work. > Reasons are below... > The first expression selects the 3rd and 4th node. > The second and 3rd expression won't select anything. This is because > you're making a logical mistake here. The 3rd expression should be : > /Node/Formgroups/Formula[@MinAmt >= $Value and $Value <= @MaxAmt]. > > This is because you need to select a value that is greater than the > MinAmt and *less than* the MaxAmt. The expression you've written can > be > > interpreted as MaxAmt <= Value <= MinAmt, which is impossible in your > XML file. So, it does not select anything. > > When written properly, your XPath should select the 3rd and 4th node. > (of the sample XML you gave) , > > Edit: And not the 2nd node. > > Hope this helps, > > Regards, > > Cerebrus. > TR wrote:
> I tried the syntax provided, but something still doen't work correctly. Why? Greater than or equal to the minimum and less than or equal to the > If I provide a value of say, 195, the expression returns record 4 from > the example previously. It should have returned records 3 and 4. maximum was your reqirement in your first two posts. The example provided in the third post was <Node> <Formgroups> <Formula MinAmt="0" MaxAmt="51" Group="0" PercentValue="0"> </Formula> <Formula MinAmt="51" MaxAmt="192" Group="51.00" PercentValue="10"> </Formula> <Formula MinAmt="192" MaxAmt="620" Group="98.00" PercentValue="15"> </Formula> <Formula MinAmt="620" MaxAmt="1409" Group="306.80" PercentValue="25"> </Formula> </Formgroups> </Node> For a value of 195 there is only one element <Formula MinAmt="192" MaxAmt="620" Group="98.00" PercentValue="15"> </Formula> matching the requirement. Unless you are changing the requirements with every post. Hello Martin,
Oops, my bad. It is correct. If you noticed it was very early in the morning. Thansk for your help... TR Show quote > TR wrote: > >> I tried the syntax provided, but something still doen't work >> correctly. If I provide a value of say, 195, the expression returns >> record 4 from the example previously. It should have returned >> records 3 and 4. >> > Why? Greater than or equal to the minimum and less than or equal to > the > maximum was your reqirement in your first two posts. > The example provided in the third post was > <Node> > <Formgroups> > <Formula MinAmt="0" MaxAmt="51" Group="0" PercentValue="0"> > </Formula> > <Formula MinAmt="51" MaxAmt="192" Group="51.00" > PercentValue="10"> > </Formula> > <Formula MinAmt="192" MaxAmt="620" Group="98.00" > PercentValue="15"> </Formula> > <Formula MinAmt="620" MaxAmt="1409" Group="306.80" > PercentValue="25"> </Formula> > </Formgroups> > </Node> > For a value of 195 there is only one element > > <Formula MinAmt="192" MaxAmt="620" Group="98.00" > PercentValue="15"> </Formula> > > matching the requirement. Unless you are changing the requirements > with every post. > |
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