使用simplehtmldom抓取9000行大表格报Call to a member function find()错误

Hey Danny, let's work through this issue step by step. That error pops up because $html->find('table', 1) is returning false—either the second table doesn't exist in your full node_list.html file, or SimpleHTMLDom is failing to parse the large document entirely (even after adjusting memory limits). Here are actionable fixes to get your script working:

1. First, Verify the Target Table Actually Exists #

Before diving into memory tweaks, confirm your full HTML file has at least two tables. Run this quick check to rule out file corruption or unexpected structure:

<?php
$content = file_get_contents('node_list.html');
// Count how many <table> tags are present in the file
$tableCount = substr_count($content, '<table');
echo "Total tables in file: " . $tableCount;
?>

If the count is less than 2, you'll need to adjust your find() index (maybe it should be 0 instead of 1). If it's 2 or more, move on to the next solutions.

2. Switch to PHP's Native DOM Extensions (Better for Large Files) #

SimpleHTMLDom is great for small documents, but it’s memory-heavy for large datasets—loads the entire DOM into memory as a custom object. PHP’s built-in DOMDocument and DOMXPath are far more efficient with memory and handle big files better. Here’s a replacement script for your use case:

<?php
$dom = new DOMDocument();
// Suppress warnings about malformed HTML (common in real-world pages)
libxml_use_internal_errors(true);
$dom->loadHTMLFile('node_list.html');
libxml_clear_errors();

$xpath = new DOMXPath($dom);
// Target the second table (XPath uses 1-based indexing)
$table = $xpath->query('//table[2]')->item(0);

if (!$table) {
    die("Could not locate the second table");
}

$rowData = [];
foreach ($table->getElementsByTagName('tr') as $row) {
    $flight = [];
    foreach ($row->getElementsByTagName('td') as $cell) {
        $flight[] = trim($cell->textContent);
    }
    if (!empty($flight)) { // Skip empty rows to clean up data
        $rowData[] = $flight;
    }
}

print_r($rowData);
?>

This should handle your 9000-row table without hitting memory limits as quickly.

3. Bump the Memory Limit Higher #

If you want to stick with SimpleHTMLDom, try increasing the memory limit further—128M might not be enough for a 9000-row table given SimpleHTMLDom’s memory-heavy structure. Run the script with:

php -d memory_limit=512M domtest.php

You can also track memory usage mid-script to see where it hits limits:

// Add this inside your loop to monitor memory usage
echo "Current memory usage: " . memory_get_usage(true) / 1024 / 1024 . "MB\n";

4. Parse Only the Target Table (Reduce Load) #

Instead of loading the entire HTML file into SimpleHTMLDom, extract just the second table’s content first, then parse that smaller chunk. This cuts down the data SimpleHTMLDom has to process:

<?php
require('simplehtmldom/simple_html_dom.php');

$content = file_get_contents('node_list.html');
// Use regex to extract all tables (adjust if your HTML has complex table attributes)
preg_match_all('/<table[^>]*>(.*?)<\/table>/s', $content, $matches);

if (isset($matches[0][1])) { // Grab the second table (index 1)
    $html = str_get_html($matches[0][1]);
    $rowData = [];
    foreach($html->find('tr') as $row) {
        $flight = [];
        foreach($row->find('td') as $cell) {
            $flight[] = $cell->plaintext;
        }
        $rowData[] = $flight;
    }
    print_r($rowData);
} else {
    die("Second table not found in the file");
}
?>

Note: Regex isn’t perfect for HTML, but it works well for simple table structures like yours.

内容的提问来源于stack exchange，提问作者Danny