Get Content textarea field put into select field

Textarea:

2000-100gram
3000-200gram
4000-300gram

 ###############
<?php
$choices = array();

    $choices = get_field('my_select_values');
    $choices = explode("\n", $choices);
    $choices = array_map('trim', $choices);
    if( is_array($choices) ) {

     echo '<select class="item_size">';
        foreach( $choices as $key => $choice ) {

        $value = explode("-", $choice);
        echo $value[0];
         echo '<option value="'.$value[0].'">' . $choice . '</option>';

        }

        echo '</select>';
    }
?>