acp-search-filters.php

<?php
/**
 * Hook to change the filter settings for a column
 */

/**
 * Unset Smart Filtering operators for a specific column
 * It is not possible to add new operators since the list of operators only contains items that are implemented
 *
 * @param array     $filter
 * @param AC\Column $column
 *
 * @return array
 */
function acp_search_filter_unset_operators_for_title_column( $filter, AC\Column $column ) {
	if ( $column instanceof ACP\Column\Post\Title ) {
		// Unset Operators (only unset is possible, otherwise it will lead to fatal errors
		unset( $filter['operators'][ array_search( 'not_equal', $filter['operators'] ) ] );
		unset( $filter['operators'][ array_search( 'begins_with', $filter['operators'] ) ] );
	}

	return $filter;
}

add_filter( 'acp/search/filters', 'acp_search_filter_unset_operators_for_title_column', 10, 2 );

/**
 * Example on how to modify the options for Smart Filtering for a specific column
 *
 * @param array     $filter
 * @param AC\Column $column
 *
 * @return array
 */
function acp_search_filters_overwrite_search_values_for_post_format_column( $filter, AC\Column $column ) {
	if ( $column instanceof ACP\Column\Post\Formats ) {
		$filter['values'] = [
			'post-format-standard' => 'Standard',
			'post-format-aside'    => 'Aside',
		];
	}

	return $filter;
}

add_filter( 'acp/search/filters', 'acp_search_filters_overwrite_search_values_for_post_format_column', 10, 2 );