Query WordPress attachments with no alt text and automatically create alt text using file name

pr_query_attachments.php

<?php
/**
 * Query WordPress attachments with no alt text
 * Automatically create alt text using file name
 * Remove this snippet once you've run it
 */
function pr_query_attachments() {
	if( did_action( 'init' ) > 1 ) {
		return;
	}
	$args = array(
    'post_type' 		=> 'attachment',
    'posts_per_page' 	=> 10, // You can increase this number here if you wish
		'meta_key'			=> '_wp_attachment_image_alt',
		'meta_compare'		=> 'NOT EXISTS'
	);
	$attachments = get_posts($args);
	if ($attachments) {
		foreach( $attachments as $post) {
			setup_postdata($post);
			error_log( $post->ID ); // This is the attachment ID
			$alt = get_post_meta( $post->ID, '_wp_attachment_image_alt', true );
			$name = $post->post_name;
			if( ! $alt ) {
				$alt = str_replace( array( '-', '_' ), ' ', $name ); // Replace dashes and underscores with spaces
				$alt = preg_replace('/\d/', '', $alt ); // Remove numbers
				$alt = trim( $alt ); // Remove white space
				$alt = ucfirst( $alt ); // Caps first letter
				if( $alt ) {
					update_post_meta( $post->ID, '_wp_attachment_image_alt', $alt );
					error_log( $alt ); // Just print the new alt tag - you can comment this line out
				}
			}
			
		}
	}
}
add_action( 'init', 'pr_query_attachments' );