php字符串中双引号替换问题

$s=str_replace(""", "", $str);

例子：

<?php
$value = "["050", "广东省", "GUANGDONG"], ["050020", "广州", "GUANGZHOU"], ["050030", "潮州", "CHAOZHOU"], ["050040", "东莞", "DONGGUAN"], ["050050", "佛山", "FOSHAN"], ["050060", "惠州", "HUIZHOU"], ["050070", "清远", "QINGYUAN"], ["050080", "汕头", "SHANTOU"], ["050090", "深圳", "SHENZHEN"], ["050100", "顺德", "SHUNDE"], ["050110", "湛江", "ZHANJIANG"], ["050120", "肇庆", "ZHAOQING"], ["050130", "中山", "ZHONGSHAN"], ["050140", "珠海", "ZHUHAI"], ["050150", "江门", "JIANGMEN"], ["050160", "阳江", "YANGJIANG"], ["050170", "韶关", "SHAOGUAN"], ["050180", "茂名", "MAOMING"], ["050190", "梅州", "MEIZHOU"], ["050200", "汕尾", "SHANWEI"], ["050210", "河源", "HEYUAN"], ["050220", "揭阳", "JIEYANG"], ["050230", "云浮", "YUNFU"], ["050240", "开平", "KAIPING"], ["050250", "台山", "TAISHAN"], ["050260", "普宁", "PUNING"], ["050270", "南沙", "NANSHA"], ["050280", "龙川", "LONGCHUAN"], ["050290", "鹤山", "HESHAN"]";
//$value2 = str_replace(""","",$value);
$value2 = str_replace(""","",$value);
echo $value2;


//$value = "字"符"串";
//$value2 = str_replace(""","",$value);
//echo $value2;
?>