PHP value of GET variable is 0?

Question

I am having problems creating a simple PHP script. The $_GET["give"] variable is always 0 in PHP, but I did define it in the URL. If it's not defined, my script redirects.

    if (isset($_GET["give"])&&$_GET["give"]!="") {
        echo "give GET detected<br />";
        $user = $_GET["give"];
        echo $_GET["give"]+$user+"<br />";
    }
    header("Location: /diamonds/"); //this document, but removing arguments.

The URL is fine, /?give=kroltan, it should echo kroltan. But instead, I get this in the browser:

   give GET detected <br>
   0

It doesn't even echo the $user variable, although it's the same value as $_GET["give"]. And no <br> after that too

dvir · Accepted Answer · 2012-06-17 14:31:03Z

6

This is PHP. You concat strings with a . and not a +.

As @MarcB said in the comments - in other words, you're doing a mathematical addition on strings, so PHP is converting your kroltan string to a 0.

String operators in PHP

edited Jun 17, 2012 at 14:31

answered Jun 17, 2012 at 14:25

dvir

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2 Comments

Marc B Over a year ago

in other words, you're doing a mathematical addition on strings, so PHP is converting your kroltan string to a 0.

dvir Over a year ago

I love your addition @MarcB; I'll add it in the answer

BjornW · Accepted Answer · 2012-06-17 14:47:03Z

1

By using a plus sign PHP thinks it is dealing with numbers and thus changes the string into a number. Which results in an integer with the value zero. Therefor you will always get the value zero back. Due to the values of the strings being zero.

If you want to combine strings you should use the dot instead of a plus sign.

So instead of:

echo $_GET["give"]+$user+"<br />";

You should use

echo $_GET["give"] . $user . "<br />";

Btw the code will always redirect, because you are not using an else statement, also why are you assigning the value of $_GET['give'] to $user and combining them in the next line? That seems odd.

answered Jun 17, 2012 at 14:47

BjornW

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1 Comment

Kroltan Over a year ago

This is a partial code, focused in the issue. In the full code the redirect is inside this if, but outside my important code (which retrieves things from a MySQL database (yes I am escaping it). Having bot the $_GET["give"] and $user was a test, I am actually using only $user, so I can put it inside strings without separating them (like "hello $user, how are you").

mensi · Accepted Answer · 2012-06-17 14:25:40Z

0

In PHP, the + operator is for algebraic addition, whereas . is used for string concatenation.

answered Jun 17, 2012 at 14:25

mensi

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Comments

drdaeman · Accepted Answer · 2012-06-17 14:25:54Z

0

You are using numeric addition (+) operator instead of string concatenation (.) one in $_GET["give"]+$user+"<br />". PHP happily converts non-numeric strings to zeroes.

answered Jun 17, 2012 at 14:25

drdaeman

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