I have an array, anArray, that I loop through, like so:
foreach ($anArray as $key) {
echo $_GET[$key];
}
I get numerous errors saying:
Undefined index: $key
Which is true, but I don't know how to get my PHP to recognise $key is a variable, and not just a string.
If I print out the list of the $_GET $key => $value pairs, and a list of $anArray, they both contain at least some of the same values.
Can anyone tell me where I'm going wrong?
Many thanks.
It already does recognize $key as a var, your syntax is correct, you can eliminate the error this way:
Check if $_GET array has $key in it first like this:
if array_key_exists($key, $_GET) {
echo $_GET[$key];
}
The error is telling you that you have values in $anArray that do not exist as indexes in $_GET.
For instance,
http://someserver/somepage.php?var1=this&var2=that
Will result in a $_GET like:
array(
'var1' => 'this',
'var2' => 'that'
)
So, if $anArray is like:
array('var1','var2','var3');
Your loop will work fine for var1 and var2, but when it gets to var3 it will issue the undefined index error.
If you can't know whether all the elements in $anArray are going to exist in $_GET, and you just wish to suppress the error notice, the usual approach is to wrap your execution block in an isset(); wrapper:
foreach ($anArray as $key) {
if (isset($_GET[$key])) {
echo $_GET[$key];
}
}
Or use array_key_exists() as suggested by @HappyMary.
$arr[$var]is supported perfectly fine.