Modify post columns in wordpress

functions.php

	<?php
	// modify post columns
	add_filter('manage_guru_employees_posts_columns', 'employees_posts_columns', 5);
	add_action('manage_guru_employees_posts_custom_column', 'employee_custom_columns', 5, 2);

	function employees_posts_columns($columns){
		unset( $columns['riv_post_thumbs'] );
		unset( $columns['date'] );

		$columns['phone_number'] = __('Phone');
		$columns['profile_image'] = __('Picture');
	    $columns['title'] = __('Employee Name');
		$columns['hire_date'] = __('Hire Date');
		$columns['email_address'] = __('Email Address');
	    return $columns;
	}
	function employee_custom_columns($column_name, $id){
	    if( $column_name === 'email_address' ){
	    	$email = get_field('email_address', $id );
	    	echo '<a href="mailto:' . $email . '">'. $email .'</a>';
	    }
	    if( $column_name === 'hire_date' ){
	    	$date = get_field('hire_date',$id);
	    	echo date( 'M dS Y', strtotime( $date ) );
	    }
	    if( $column_name === 'profile_image'){
	    	echo '<img src="' . get_field( $column_name, $id )['sizes']['thumbnail'] . '"/>';
	    }
	}
	?>