need more detail tying in Session_start() to a select statement

问题

Still banging my head, but I think an answer may help me see how things really work. I always sucked at languages, but I figure with your help I can brute force this.

So I am just going to post the whole code so as not to cause confusion.

<html>
<head>
<title>Change a player</title>
</head>
<BODY >
<?php
 include "inc.php";
 session_start();

 print 'Select week for season: ';
   print $this_season;
##the week drop down query#
$wquery=
"select week_num,week_name
from stats_week
where season=$this_season
order by week_num";
    $wresult=mysql_query($wquery);
print'<form action="changeplayer_2.php" method="post">';
    session_start();
        print"<select name='Week_select'> <br>";
        while ($wrow=mysql_fetch_array($wresult))
    { 
    print '<option value="'.$wrow['week_num'].'">'.'week             '.$wrow['week_num'].'     '.$wrow['week_name'].'</option><br>\n';  
    }
print "</select><br><br>";#
print'<button type="submit" >Next</button>';
$varWeek=$_POST['Week_select'];
    print"</form>";
$_SESSION['week'] = $varWeek;
?>  
</body>
</html>

So, I don't know how to get 'Week_select' to be assigned to $_SESSION['week']. Above code was my last ditch effort. Secondly, once I assign something to the Session, how do I clear it out later so it doesn't keep popping up? Bonus question

print 'Select week for season: ';
   print $this_season;

Is the only way I can make the both the statement and the variable to display. When I do

print 'Select week for season: '$this_season;

I don't get the variable displayed, also when I do

print 'Select week for season: $this_season';

I get Select week for season: $this_season displayed

回答1:

session_start() should be placed before output or any $_SESSION interaction. And only once.

<?php
session_start();
?>
<html>
<head>
<title>Change a player</title>
</head>
<BODY >
<?php
 include "inc.php";
// etc...
?>
</body>
</html>

UPDv1:

if you need to remove something from session, then you can perform:

<?php unset($_SESSION['something']); ?>

UPDv2:

If you need tu put entire select into $_SESSION, you may do:

ob_start();

print "<select name='Week_select'>";

while ($wrow=mysql_fetch_array($wresult))
    { print '<option value="'.$wrow['week_num'].'">week '.$wrow['week_num'].' '.$wrow['week_name'].'</option>'.PHP_EOL; }

print "</select>";

$_SESSION['something'] = ob_get_clean();

// var_dump($_SESSION);

回答2:

When displaying (print/echo) a variable with a specific string, you must concatenate the two with " . " (dot)

print 'Select week for season: ' . $this_season;

回答3:

Session unset and destroy: here Or you could just unregister the one variable: session_unregister($week)

And yes you should only have once session_start per page ideally before anything is output. And the correct way to print is to concatenate:

print "Select week for season: " . $this_season;

回答4:

Place your session_start() at the top of the html. Remove the second session_start() in the page.

Try printing/echoing your $_SESSION['week'] to check if it has a value.

print $_SESSION['week'];

回答5:

Your first question:

Part 1

To set a session the code should be inserted before the HTML tags. Read code below:

<?php
session_start();
$_SESSION['week'] = $this_season;
?>

<html>
<head>
//your code here
</head>
<body>
//your code here
</body>
</html>

Part 2

If you want to remove a session completely you can use the following code, which will destroy the session:

<?php session_destroy(); ?>

Or if you only want to clear a session you can use the following code:

<?php unset($_SESSION['week']); ?>

It will clear the session value.

Your second question:

To merge both print syntax together you need to use a dot "." . In some other language "+" is used. The process is called concatenation

Your new code should be:

print 'Select week for season: ' . $this_season;

This means that you want to print the string 'Select week for season: ' followed by the variable $this_season.

来源：https://stackoverflow.com/questions/15962443/need-more-detail-tying-in-session-start-to-a-select-statement

标签

php

session-variables