错误：value of type 'string' has no member 'generator'
解释：这个是oc中的写法。
比如，像下面这样遍历字符
for i in "swift".Charactor
{
print(i);
}
错误：value of type 'string' has no member 'generator'
解释：这个是oc中的写法。
比如，像下面这样遍历字符
for i in "swift".Charactor
{
print(i);
}