索引为变量的$ _SESSION不停留

Question

I am setting a $_SESSION variable with variable index but it does not hold.

if (isset($_GET['reply']))
{
 echo  $_SERVER['QUERY_STRING']; // example output: reply&55
 $vals = explode('&',$_SERVER['QUERY_STRING']); // val[1] = 55
 session_start();
 $_SESSION[strval($vals[1])] = 1;  //tried as int first and now convert to string
 print_r($_SESSION);

 }

when i look at the contents of $_SESSION it shows: Array ( [iamloggedIn] => 1 [userID] => 5 [55] => 1 )

It is showing two variables set with normal string indexes (eg $_SESSION['userID'] = 5) , and then the last session variable just set.

Now if this if statement is called again with a new value in val[1], say 59 for example, it overwrites the last one and my print_r will show something like: Array ( [iamloggedIn] => 1 [userID] => 5 [59] => 1 )

It is not creating a new session variable.

Is this because I am using a variable as the index? I tried the index variable as an integer first and now as a string but the result is the same.

Answer 1

The $_SESSION variable must be an associative array, thus

$_SESSION['33'] = 'foo';

Won't work unfortunately, because '33' despite being a string will be casted as an integer key of the array. For more details on how keys are automatically casted:

http://us.php.net/manual/en/language.types.array.php

Strings containing valid integers will be cast to the integer type. Eg the key "8" will actually be stored under 8. On the other hand "08" will not be cast, as it isn't a valid decimal integer.

Floats are also cast to integers, which means that the fractional part will be truncated. Eg the key 8.7 will actually be stored under 8.

Bools are cast to integers, too, ie the key true will actually be stored under 1 and the key false under 0.

Null will be cast to the empty string, ie the key null will actually be stored under "".

Answer 2

Judging only by what you are showing us, you are right, print_r($_SESSION) should be displaying:

Array([iamloggedIn] => 1, [userID] => 5, [55] => 1, [59] => 1)

I'd try concatenating a string before the index, like this:

$_SESSION['example' . strval($vals[1])] = 1;

And accessing it through $_SESSION['example55'] , for example.