如何使用PHP从外部XML文件中提取所有“ TickerSymbol”元素？

Question

I would like to write a PHP script to extract all elements (and only ticker symbols) from the following external page: https://www.predictit.org/api/marketdata/all/

So at the time of this writing, the output would be

VAGOV17

DEM.VAGOV17

GOP.VAGOV17

NJGOV17

...

I've tried variations of loadXML() and DOMDocument::getElementsByTagName() but kept getting errors. The XML in the page above appears to be well formed.

Thanks in advance!

Answer 1

You could use SimpleXML to load a remote url .

Then you can use a foreach to loop through all of the data.

Example:

$context  = stream_context_create(array('http' => array('header' => 'Accept: application/xml')));
$url = 'https://www.predictit.org/api/marketdata/all/';

$xml = file_get_contents($url, false, $context);
$elements = simplexml_load_string($xml);

foreach ($elements->Markets->MarketData as $marketData) {

    echo $marketData->TickerSymbol . "<br>";

    foreach ($marketData->Contracts->MarketContract as $contract) {
        echo "-" . $contract->TickerSymbol . "<br>";
    }
}

Will result in:

VAGOV17
-DEM.VAGOV17
-GOP.VAGOV17
NJGOV17
-DEM.NJGOV17
-GOP.NJGOV17
MAYOR.NYC2017
-BDB.MAYOR.NYC2017
-WEINER.MAYOR.NYC2017
-QUINN.MAYOR.NYC2017
-STRINGER.MAYOR.NYC2017

Etc..

Answer 2

Here is your Code. Let me know working or not

Hoping your xml file called 'all.xml'

<?php 

if (file_exists('all.xml')) 
{
    $xml = simplexml_load_file('all.xml');

     foreach ($xml as $k)
     {
        $tag =  $k->getName();
        $i = 0;
        foreach($xml->$tag->children() as $key)
        {
            $marketData = $key->getName();

            echo $xml->$tag->MarketData[$i++]->TickerSymbol . "<br>";
        }
     }
}
else
 {
    exit('Failed to open all.xml.');
}