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@NogDogNov 06.2006 — #Just to elaborate on the variable evaluating as true/false issue, there are several type/value combinations which will evaluate as FALSE in a [b]if($var)[/b] expression. See the "Converting to Boolean" section of [url=http://www.php.net/manual/en/language.types.boolean.php]this manual page[/url] for all the possibilities. If the variable does not match one of those conditions for being FALSE, then it will be evaluated as TRUE.
If you want to check to see if a variable is expressly set as a boolean TRUE or FALSE value, then you need to use a type-sensitive comparison operator ([b]===[/b] or [b]!==[/b] instead of [b]==[/b] or [b]!=[/b]):
if statements and TRUE
I’m studying PHP and web forms and would like some clarity on what’s happening here with IF/TRUE statements.
In the below sample, if someone submits their email address it is stored in $email? which will then evaluate as TRUE. Is their email address (the stored value in $email) now being overwritten by the word TRUE?
[CODE]// Check for an email address.
if (strlen($_POST[’email’]) > 0) {
$email = TRUE;
} else {
$email = FALSE;
echo ‘<p>You forgot to enter your email address!</p>’;
}[/CODE]
At the end of the IF statements, there is the ($name && $email && etc) stuff where there is no else after it. Is it looking to see if TRUE is flagged to all of these?
[CODE]if ($name && $email && $username && $password) { // If everything’s okay.
// Register the user.
echo ‘<p>You are now registered.</p>’;
} else { // Something’s not TRUE.
echo ‘<p>Please go back and try again.</p>’;
}[/CODE]
Also, sometimes I just see “if ($var);” then straight on to something else without an interrogative. What is happening with these? I gather there’s a truth test but what passes as true if there seems to be no specific test accociated with it? Some clarity on these issue would help me understand what underlies these type of IFs
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@NogDogNov 06.2006 — #Just to elaborate on the variable evaluating as true/false issue, there are several type/value combinations which will evaluate as FALSE in a [b]if($var)[/b] expression. See the "Converting to Boolean" section of If you want to check to see if a variable is expressly set as a boolean TRUE or FALSE value, then you need to use a type-sensitive comparison operator ([b]===[/b] or [b]!==[/b] instead of [b]==[/b] or [b]!=[/b]):
[code=php]
if($var === TRUE) {
// or:
if($var !== FALSE) {
[/code]