java软件工程师学php-7.Map被称作关联数组

java程序员学php - 7. Map被称作关联数组
如：
$map['BJ'] = 'Beijing';
$map['SH'] = 'Shanghai';

遍历这个关联数组：
foreach($map as $abbr=>$full_name){
echo "$abbr is short for $full_name";
}