PHP Array key strings without quotation marks
I am moving the files to the server and is using variables like $_GET[mode] without ''(single quotes) in 'mode'. It works perfectly locally but on the server i am getting notices..开发者_如何学JAVA How can i overcome this?here is my phpinfo file phpinfo Is there any way we can have same behavior to work on server as well?
How can you overcome the E_NOTICE
s that complain that you forgot quotes around your strings?
Add quotes around your strings.
$_GET['mode']
Also it sounds like the error_reporting
level on your local server is not sufficient. It should be high, so that you see these sorts of mistakes as you develop your website/application.
On your production server it may be set lower.
Quoting the PHP Manual on Arrays:
Why is $foo[bar] wrong?
Always use quotes around a string literal array index. For example,
$foo['bar']
is correct, while$foo[bar]
is not. But why? It is common to encounter this kind of syntax in old scripts:
<?php
$foo[bar] = 'enemy';
echo $foo[bar];
// etc
?>
This is wrong, but it works. The reason is that this code has an undefined constant (
bar
) rather than a string ('bar'
- notice the quotes). PHP may in future define constants which, unfortunately for such code, have the same name. It works because PHP automatically converts a bare string (an unquoted string which does not correspond to any known symbol) into a string which contains the bare string. For instance, if there is no defined constant namedbar
, then PHP will substitute in the string'bar'
and use that.
So, in other words: mode
is an undefined constant.
Quoting the PHP Manual on Constants:
If you use an undefined constant, PHP assumes that you mean the name of the constant itself, just as if you called it as a string (CONSTANT vs "CONSTANT"). An error of level
E_NOTICE
will be issued when this happens. See also the manual entry on why$foo[bar]
is wrong (unless you firstdefine()
bar as a constant). If you simply want to check if a constant is set, use thedefined()
function.
Solution: put quotes around the key.
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