Getting error to display radio button value in General Settings page

I’m constantly getting the errors bellow when printing the radio button values from General Settings screen:

Illegal string offset ‘service’ in F:\wamp\www\plugin-tester\wp-content\themes\twentythirteen\functions.php on line 565

Illegal string offset ‘service’ in F:\wamp\www\plugin-tester\wp-content\themes\twentythirteen\functions.php on line 568

Here is the code which I added to functions.php file:

add_filter('admin_init', 'myservice_register_function');
function myservice_register_function(){
    register_setting('general', 'my_service', 'esc_attr');
    add_settings_field('my_service', '<label for="service_need">'.__('Do You need My    Service' , 'my_service' ).'</label>' , 'service_function', 'general');
}

function service_function(){
    $options = get_option( 'my_service', '');
    //  $options = get_settings( 'my_service');

    if($options['service'] == 'YES') { //line number 565
        echo 'Yes, Service Need'; 
    }
    if($options['service'] == 'NO') { // line number 568
        echo 'No Need Service';
    }
    $html = '<input type="radio"  name="my_service[service]" value="YES"/>'; 
    $html .= '<label> NEED </label>'; 

    $html .= '<input type="radio"  name="my_service[service]" value="NO"/>'; 
    $html .= '<label > NO NEED </label>'; 

    echo $html;
}

What’s the mistake?

Solutions Collecting From Web of "Getting error to display radio button value in General Settings page"

Apart from the isset issue, pointed by Rarst, there’s an error in the sanitization function. esc_attr seems not to work with radio buttons, using esc_sql does the job.
You’re also missing the checked state for the buttons:

add_filter( 'admin_init', 'myservice_register_function' );

function myservice_register_function()
{
    register_setting( 'general', 'my_service', 'esc_sql' );
    add_settings_field(
        'my_service', 
        '<label for="service_need">'.__('Do You need My Service' , 'my_service' ).'</label>' , 
        'service_function', 
        'general'
    );
}

function service_function()
{
    $options = get_option( 'my_service', '');
    $yes = $no = '';
    if( isset( $options['service'] ) )
    {
        if( $options['service'] == 'YES') 
        {
            echo 'Yes, Service Need<br />'; 
            $yes = ' checked="checked"';
        }
        if( $options['service'] == 'NO') 
        {
            echo 'No Need Service<br />';
            $no = ' checked="checked"';
        }
    }
    ?>
    <input type="radio"  name="my_service[service]" value="YES"<?php echo $yes; ?> />
    <label> NEED </label>

    <input type="radio"  name="my_service[service]" value="NO"<?php echo $no; ?> />
    <label> NO NEED </label> 
    <?php
}