Elements in PHP tables: an in-depth analysis of the differences between columns and rows

In the table element, columns (

) contain vertically arranged data items, representing specific fields or attributes; rows ( ) contain horizontally arranged column sets, representing data records or entities. Using PHP's DOM operations, we can access, add, delete and modify elements in the table to build flexible and powerful web page layouts.

Elements in PHP tables: An in-depth analysis of the difference between columns and rows

Introduction
The table element is the basic element for building web page layout and data management. In PHP, we can create a table using the <table> tag, and then use <code><tr> (rows) and <code><td> (columns) Tags define their structure. Understanding the difference between columns and rows in a table is critical to effectively processing and manipulating data. <p><strong>The difference between columns and rows</strong></p> <ul><li><strong>Columns (<code><td>): Columns contained in the table A single data item arranged vertically. They represent specific fields or properties. <li><strong>Row (<code><tr>): Row contains a collection of columns arranged horizontally. They represent data records or entities. <p><strong>Practical case</strong></p> <p>Let us create a simple table with 3 rows and 2 columns of user data: </p><div class="code" style="position:relative; padding:0px; margin:0px;"><pre class='brush:php;toolbar:false;'>&lt;table&gt; &lt;tr&gt; &lt;td&gt;John&lt;/td&gt; &lt;td&gt;Doe&lt;/td&gt; &lt;/tr&gt; &lt;tr&gt; &lt;td&gt;Jane&lt;/td&gt; &lt;td&gt;Smith&lt;/td&gt; &lt;/tr&gt; &lt;tr&gt; &lt;td&gt;Bob&lt;/td&gt; &lt;td&gt;Green&lt;/td&gt; &lt;/tr&gt; &lt;/table&gt;</pre><div class="contentsignin">Copy after login</div></div><p>In this In the example, we have: </p><ul><li>3 rows (user records) </li><li>2 columns (username and userlastname) </li></ul><p><strong>Access columns and Rows </strong></p><p> We can access the columns and rows in the table using the <code>querySelectorAll() method:

// 获取所有列
$cols = $table->querySelectorAll('td');

// 获取所有行
$rows = $table->querySelectorAll('tr');

Manipulate columns and rows

Once we have the columns and rows, we can perform various operations such as adding, removing, or modifying their contents:

Add content (add new rows):

$newRow = $table->insertRow(-1);
$newRow->insertCell(-1)->textContent = 'New User';
$newRow->insertCell(-1)->textContent = 'New Last Name';

Delete content (delete specific rows):

$rowToRemove = $table->rows[2];
$rowToRemove->remove();

Modify content (modify specific cells):

$cellToUpdate = $table->rows[0]->cells[0];
$cellToUpdate->textContent = 'Updated User';

Conclusion

By understanding the difference between columns and rows in tables, we can process and manipulate data efficiently. By using PHP's DOM operations, we can access, add, delete, and modify elements in the table to create flexible and powerful web page layouts.

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