Re: weird isset problem
| From: | Philip Olson | Date: | Thu, 29 Mar 2001 23:03:10 +0000 |
| Subject: | Re: weird isset problem | ||
| References: | 1 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-46177@lists.php.net to get a copy of this message | ||
What are you wanting to print? Here's a set of examples that may help
understand what's happening with your code. In short, isset() is not
being used properly.
// if $var is set, this will return 1. if not set then it will return 0.
// essentially, you don't want to print this directly as you've seen, it
// gives us 1 or 0.
isset($var)
// these checks check for true.
if ( isset($var) == true ) {
print 'this is set';
}
if ( isset($var) == 1 ) {
print 'this is set';
}
if ( isset($var) ) {
print 'this is set';
}
// these checks check for false.
if ( isset($var) == false ) {
print 'this is not set';
}
if ( isset($var) == 0 ) {
print 'this is not set';
}
if ( !isset($var) ) {
print 'this is not set';
}
// This will check whether $var is empty but this way causes error if
// error_reporting setting E_NOTICE is on (undefined variable)
if ($var) {
print 'this is set';
}
Which brings us to empty(), empty is similar to isset, here's an example
of difference :
$var = 0;
if ( empty($var) ) {
print 'this will print if $var is not set,0, or empty "" ';
}
if ( isset($var) ) {
print 'this is set, could be set to anything, including 0 or "" ';
}
Wow this got long, hopefully it makes sense :)
regards,
philip
On Thu, 29 Mar 2001, Matthew Hanna wrote:
> Hi! I have this weird thing happening here and I just can't see the problem.
> Can someone look at this and tell me if you see what is wrong?
> Below is a code snippet I am using and the output from the code. As can
> be seen in the output all the $config[*] stuff are set. The if statement still
> gets executed though as if one or more $config[*] isn't set. Inside of the
> if statement I checked again and sure enough, they are still set even though
> the program makes it into the if statement.
> I am so confused.
>
> Thanks in advance!
> Matthew Hanna
> hanna@clemson.edu
>
> ---- Code ----
> print isset($config["harvester_list"]) ."\n1\n";
> print isset($config["download_list"]) . "\n2\n";
> print isset($config["linkchecker_list"]) . "\n3\n";
> print isset($config["offline_list"]) . "\n4\n";
> print isset($config["spider_list"]) . "\n5\n";
> if (!isset($config["havester_list"]) ||
> !isset($config["download_list"]) ||
> !isset($config["linkchecker_list"]) ||
> !isset($config["offline_list"]) ||
> !isset($config["spider_list"])) {
> print "-----------------------------\n";
> print isset($config["harvester_list"]) ."\n1\n";
> print isset($config["download_list"]) . "\n2\n";
> print isset($config["linkchecker_list"]) . "\n3\n";
> print isset($config["offline_list"]) . "\n4\n";
> print isset($config["spider_list"]) . "\n5\n";
>
> die("Agent Automated System Lists Not Found!\n");
> }
>
> ---- Output -----
> 1
> 1
> 1
> 2
> 1
> 3
> 1
> 4
> 1
> 5
> -----------------------------
> 1
> 1
> 1
> 2
> 1
> 3
> 1
> 4
> 1
> 5
> Agent Automated System Lists Not Found!
>