php-PHP字符串类型如何转为数组类型

$arr是字符串类型，单引号中是数组语法，如何将该字符串转换为数组类型？

$arr = 'array("张三"=>"1988","李四"=>"1990","王五"=>"1989")';foreach($arr as $key => $value){        echo "姓名:".$key."-年份:".$value."
";}