使用php中的DOMDocument从xml获取最后一个子节点

Question

Here is my xml:

<details> 
        <car>
          <id>61XZB6</id>
          <Jan-01-14>20</Jan-01-14>
          <Jan-02-14>435</Jan-02-14>
          <Jan-03-14>454</Jan-03-14>
          <Jan-04-14>768</Jan-04-14>
          <Jan-05-14>24</Jan-05-14>
          <Jan-06-14>675</Jan-06-14>
          <Jan-07-14>213</Jan-07-14>
          <Jan-08-14>44</Jan-08-14>
          <Jan-09-14>565</Jan-09-14>
          <Jan-10-14>80</Jan-10-14>
          <Jan-11-14>998</Jan-11-14>
          <Jan-12-14>67</Jan-12-14>
          <Jan-13-14>77</Jan-13-14>
          <Jan-14-14>909</Jan-14-14>
          <Jan-15-14>34</Jan-15-14>
          <Jan-16-14>887</Jan-16-14>
          <Jan-17-14>767</Jan-17-14>
          <Jan-18-14>545</Jan-18-14>
          <Jan-19-14>67</Jan-19-14>
          <Jan-20-14>787</Jan-20-14>
          <Jan-21-14>898</Jan-21-14>
          <Jan-22-14>435</Jan-22-14>
          <Jan-23-14>42</Jan-23-14>
          <Jan-24-14>232</Jan-24-14>
          <Jan-25-14>234</Jan-25-14>
          <Jan-26-14>675</Jan-26-14>
          <Jan-27-14>46</Jan-27-14>
          <Jan-28-14>546</Jan-28-14>
          <Jan-29-14>88</Jan-29-14>
          <Jan-30-14>0</Jan-30-14>
          <Jan-31-14>0</Jan-31-14>
        </car>
     </details>

My query is how to check the last node inside each tag before inserting a new node to each tag.Thanks in advance for any sort of help extended.

Answer 1

If I understand you correctly you would like to check for the last element in each car element node? Well, Xpath hast two methods position() and last() that can be used in a condition.

Select the car nodes

/details/car

Select the child element nodes of the car nodes

/details/car/*

Add a condition to limit the selection to the last node

/details/car/*[last()]

Full example: https://eval.in/145531

$dom = new DOMDocument();
$dom->loadXml($xml);
$xpath = new DOMXpath($dom);

foreach ($xpath->evaluate('/details/car/*[last()]') as $node) {
  var_dump(
    $node->nodeName,
    $node->nodeValue
  );
}

Output:

string(9) "Jan-31-14"
string(1) "0"

HINT!

Flexible element names are really bad style, you will not be able to define them in a schema. If possible I suggest you change them to something like <amount date="Jan-31-14">0</amount>