推 john0227 :$_SESSION["$a"]跟$_SESSION[$a]兩個的差異性10/18 15:14
→ john0227 :我想知道↑10/18 15:15
// 你自己試驗一下這個就知道了
$var = "test";
echo 'This is a $var'; // This is a $var
echo 'This is a {$var}'; // This is a {$var}
echo "This is a $var"; // This is a test
echo "This is a {$var}"; // This is a test
echo 'This is a "$var"'; // This is a "$var"
echo 'This is a "{$var"'; // This is a "{$var}"
echo "This is a '$var'"; // This is a 'test'
echo "This is a '{$var}'"; // This is a 'test'
以單引號括住的字串為純字串，不含變數
而已雙引號括住的字串中可以插入變數，php 會解析。
所以 echo $_SESSION["$a"]; 和 echo $_SESSION[$a]; 的結果無異
只是 "$a" 要多打兩個雙引號，除非你要做出啥驚天動地的事情，像是
for ($num = 0; $num < 10; $num++) {
$r += $_SESSION["var$num"];
//相當於 $r = $_SESSION['var0'] + $_SESSION['var1'] + ... + $_SESSION['var9']
}
之類的事情..不然那個雙引號是打心酸的 ...
如果要表示的只是單純字串.. 用單引號似乎效能會比較好(?)
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※ 編輯: foxzgerald 來自: 61.223.230.165 (10/19 00:19)