PHP - Check GET Variables Exist And Not Empty - php

Question

I want to check the GET variables are not empty, I tried ways but they didn't work.
So I had the code like this:
$u = isset($_GET["u"]);
$p = isset($_GET["p"]);
if ($u !== "" && $p !== "") {
//something
} else {
//do something
}
The I checked the code by sending create.php?u=&p=, but the code didn't work. It kept running the //do something part. The I tried:
echo $u;
echo $p;
It returned 1 and 1. Then I changed it to:
if ($u !== 1 && $p !== 1 && $u !== "" && $p !== "") {
//something
} else {
//do something
}
But it continued to run //do something.
Please help.

Answer 1

You can just use empty which is a PHP function. It will automatically check if it exists and whether there is any data in it:
if(empty($var))
{
// This variable is either not set or has nothing in it.
}
In your case, as you want to check AGAINST it being empty you can use:
if (!empty($u) && !empty($p))
{
// You can continue...
}
Edit: Additionally the comparison !== will check for not equal to AND of the same type. While in this case GET/POST data are strings, so the use is correct (comparing to an empty string), be careful when using this. The normal PHP comparison for not equal to is !=.
Additional Edit: Actually, (amusingly) it is. Had you used a != to do the comparison, it would have worked. As the == and != operators perform a loose comparison, false == "" returns true - hence your if statement code of ($u != "" && $p != "") would have worked the way you expected.
<?php
$var1=false;
$var2="";
$var3=0;
echo ($var1!=$var2)? "Not Equal" : "Equal";
echo ($var1!==$var2)? "Not Equal" : "Equal";
echo ($var1!=$var3)? "Not Equal" : "Equal";
echo ($var1!==$var3)? "Not Equal" : "Equal";
print_r($var1);
print_r($var2);
?>
// Output: Equal
// Output: Not Equal
// Output: Equal
// Output: Not Equal
Final edit: Change your condition in your if statement to:
if ($u != "" && $p != "")
It will work as you expected, it won't be the best way of doing it (nor the shortest) but it will work the way you intended.
Really the Final Edit:
Consider the following:
$u = isset($_GET["u"]); // Assuming GET is set, $u == TRUE
$p = isset($_GET["p"]); // Assuming GET is not set, $p == FALSE
Strict Comparisons:
if ($u !== "")
// (TRUE !== "" - is not met. Strict Comparison used - As expected)
if ($p !== "")
// (FALSE !== "" - is not met. Strict Comparison used - Not as expected)
While the Loose Comparisons:
if ($u != "")
// (TRUE != "" - is not met. Loose Comparison used - As expected)
if ($p != "")
// (FALSE != "" - is met. Loose Comparison used)

Answer 2

You need !empty()
if (!empty($_GET["p"]) && !empty($_GET["u"])) {
//something
} else {
//do something
}
Helpful Link

Answer 3

if ($u !== 1 && $p !== 1 && $u !== "" && $p !== "")
why are you using "!==" and not "!=".
to always simplify your problem solve the logic on paper once using the runtime $u and $p value.
To check if $_GET value is blank or not you can use 2 methods.
since $_GET is an array you can use if(count($_GET)) if you have only u and p to check or check all incoming $_GET parameters.
empty function #Fluffeh referred to.
if($_GET['u']!=""&&$_GET['p']!="")
Hope it helps thx

Answer 4

In you code you should correctly check the variable existence like
if ($u != NULL && $p != NULL && $u != 0 && $p != 0) {
//something
} else {
//do something
}

Answer 5

Wow! I was so dumb... isset returns a boolean. I fixed my problem now. Thank you for answering anyway :)
This fixes:
$u = $_GET["u"];
$p = $_GET["p"];