Topic awaiting preservation: what in the world is '.=' ?

I'm building a little app using PayPal IPN and the following is in their PHP example code-

$header .= "POST /cgi-bin/webscr HTTP/1.0\r\n";

Could someone be kind enough to explain this little snippet of code to me?

.= is not in my PHP books and I've looked at php.net already.

Thanks in advance for clearing up this mystery.

.= is for appending something to a variable...

$display = "a";
$display .= "b";

the value of $display is now "ab"

basically. this:

$display .= "b";

is equal to this:

$display = $display . "b";

(the period concotinates the strings)

http://www.php.net/manual/en/language.operators.assignment.php

- you would have found it there, but it is kind of hidden.

Basically, it's an assignment that has the sideeffect of concenating two strings.

And yes, the dot (.) is a pretty dumb idea for any control character in a language.
It's exactly two-by-two pixels wide, and this *after* I increased the font size.
Now, go find a missing dot on a 1600x1200 screen ;-)

it's the magical dot

You swallow it and it makes the world go all funny. See, years ago we came up with a better way to distribute our black pills so they are all disguised as dots now...now there's all over the web...

Err...I shouldn't have told you that...

Going to have to kill you now....

Tyberius Prime: I don't think it's that hidden. Norm was looking for an operator, he might have had a look in the documentation or have output his value before and after the mysterious line. Whatever.

Regarding your note about the screen size of the dot. On french keyboards the ; and the : are on two consecutive keys, thus it's easy to make a typo. And I often end up trying to figure exactly where are those 2-3 missing pixels ... where a simple regex-replacement should fix my problem

Mathieu "POÏ" HENRI

And to clarify:

PS:

quote:

---

concotinates

---

TP:

quote:

---

concenating

---

Its actually concatenate (and concatenating) from the Latin for chain and it basically allows you create a 'chain' by adding in various 'links'. It is also a pain to spell as I have had to change the spelling twice in this post

___________________
Emps

FAQs: Emperor

Thanks!

I knew that the '.' was used to concatonate, but I wasn't sure if it did so when used with the '=' It looks like the answer is 'Yes'

well, I consider such a statement:

"In addition to the basic assignment operator, there are "combined operators" for all of the binary arithmetic and string operators that allow you to use a value in an expression and then set its value to the result of that expression."

without having a list of them (how hard could it have been? They're right there in the code of php, just copy paste 'em...),
to be at least slightly hidden and unworthy of the otherwise good php documentation.