php scrapping and outputting a specific value or number in a given tag

Question

so I\'m very new to php. But with some help, I\'ve figured out how to scrape a site if it has a tag identifier like h1 class=____

And even better, I\'ve figured out how

Answer 1

If you want to use third party library you can use https://github.com/rajanrx/php-scrape

<?php

use Scraper\Scrape\Crawler\Types\GeneralCrawler;
use Scraper\Scrape\Extractor\Types\MultipleRowExtractor;

require_once(__DIR__ . '/../vendor/autoload.php');
date_default_timezone_set('UTC');

// Create crawler
$crawler = new GeneralCrawler('https://coinmarketcap.com/');

// Setup configuration
$configuration = new \Scraper\Structure\Configuration();
$configuration->setTargetXPath('//table[@id="currencies"]');
$configuration->setRowXPath('.//tbody/tr');
$configuration->setFields(
    [
        new \Scraper\Structure\TextField(
            [
                'name'  => 'Name',
                'xpath' => './/td[2]/a',
            ]
        ),
        new \Scraper\Structure\TextField(
            [
                'name'  => 'Market Cap',
                'xpath' => './/td[3]',
            ]
        ),
        new \Scraper\Structure\RegexField(
            [
                'name'  => '% Change',
                'xpath' => './/td[7]',
                'regex' => '/(.*)%/'
            ]
        ),
    ]
);

// Extract  data
$extractor = new MultipleRowExtractor($crawler, $configuration);
$data = $extractor->extract();
print_r($data);

will print out following:

Array
(
    [0] => Array
        (
            [Name] => Bitcoin
            [Market Cap] => $42,495,710,233
            [% Change] => -1.09
            [hash] => 76faae07da1d2f8c1209d86301d198b3
        )

    [1] => Array
        (
            [Name] => Ethereum
            [Market Cap] => $28,063,517,955
            [% Change] => -8.10
            [hash] => 18ade4435c69b5116acf0909e174b497
        )

    [2] => Array
        (
            [Name] => Ripple
            [Market Cap] => $11,483,663,781
            [% Change] => -2.73
            [hash] => 5bf61e4bb969c04d00944536e02d1e70
        )

    [3] => Array
        (
            [Name] => Litecoin
            [Market Cap] => $2,263,545,508
            [% Change] => -3.36
            [hash] => ea205770c30ddc9cbf267aa5c003933e
        )
   and so on ...

I hope that helps you :)

Disclaimer: I am author of this library.

Answer 2

if you only care about that change percentage, try this and remove the whole foreach section:

$query = "//tr[@id='id-ethereum']/td[contains(@class, 'percent-24h')]";
$entries = $xpath->query($query);

echo $entries->item(0)->getAttribute('data-usd'); //-5.15

here are the rest of the columns:

$xpath = new DOMXPath($doc);

$market_cap = $xpath->query("//tr[@id='id-ethereum']/td[contains(@class, 'market-cap')]");
echo $market_cap->item(0)->getAttribute('data-usd'); //30574084827.1


$price = $xpath->query("//tr[@id='id-ethereum']/td/a[contains(@class, 'price')]");
echo $price->item(0)->getAttribute('data-usd'); //329.567

$circulating_supply = $xpath->query("//tr[@id='id-ethereum']/td/a[@data-supply]");
echo $circulating_supply->item(0)->getAttribute('data-supply'); //92770467.9991


$volume = $xpath->query("//tr[@id='id-ethereum']/td/a[contains(@class, 'volume')]");
echo $volume->item(0)->getAttribute('data-usd'); //810454000.0


$percent_change = $xpath->query("//tr[@id='id-ethereum']/td[contains(@class, 'percent-24h')]");
echo $percent_change->item(0)->getAttribute('data-usd'); //-3.79