get_default_primary_column_name example

    /** * Gets the name of the primary column. * * @since 4.3.0 * * @return string The name of the primary column. */
    protected function get_primary_column_name() {
        $columns = get_column_headers( $this->screen );
        $default = $this->get_default_primary_column_name();

        /* * If the primary column doesn't exist, * fall back to the first non-checkbox column. */
        if ( ! isset( $columns[ $default ] ) ) {
            $default = self::get_default_primary_column_name();
        }

        /** * Filters the name of the primary column for the current list table. * * @since 4.3.0 * * @param string $default Column name default for the specific list table, e.g. 'name'. * @param string $context Screen ID for specific list table, e.g. 'plugins'. */

/** * Gets a list of all, hidden, and sortable columns. * * @since 3.1.0 * * @return array */
    protected function get_column_info() {
        $columns  = get_column_headers( $this->_screen );
        $hidden   = get_hidden_columns( $this->_screen );
        $sortable = array();
        $primary  = $this->get_default_primary_column_name();

        return array( $columns, $hidden, $sortable, $primary );
    }

    /** * Gets a list of columns. * * @since 3.1.0 * * @return array */