foreach用法

Question

帮我解释运行原理和$diqusql.="'{$i}'"的含意

 $diqusql="diyu IN(";

        foreach($diqu as $i){

            $diqusql.="'{$i}',";

        }

        $diqusql=rtrim($diqusql, ",").")"

Answer 1

foreach是遍历数组的语句，标准用法是：foreach（数据类型 标识符 in 表达式）

e.g:

$person = array(
  "name1" => "peter",
  "name2" => "lisi"
);
foreach ($person as $person_value) {
  echo "姓名：" . $person_value;
  echo "<br>";
}