In article <[EMAIL PROTECTED]>,
[EMAIL PROTECTED] (Jordan Elver) wrote:
> if($var) {
> // variable is here
> }
>
> But I've noticed that a lot of people do:
>
> if(isset($var)) {
> // variable is here
> }
>
> What's the difference and which is the best way?
Turn up error reporting to E_ALL, and you'll notice a difference. Set $var
to FALSE, NULL, an empty string, or zero, and you'll notice a difference.
"if($var)" tests for a true value
"if($isset($var))" does what its name suggests
The first option often can have a convenience value, where error_reporting
is not at E_ALL and where lumping all "false" values together and all
"true" values together is acceptable to you. Where you genuinely need to
distinguish between a set vs. an unset variable, use isset(). Where you
need to distinguish between unset, set-with-"false"-value, and
set-with-"true"-value, use isset() followed by either empty() or !$var.
Where you need to make even finer distinctions, use isset() followed by the
=== operator.
(By putting the isset() test first, you avoid error messages: if the
comparison fails that first "isset" test, then it never gets passed on to
the next comparison, where an error message would have been generated by
the attempt to do a comparison against an unset variable.)
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