Re: php: assignment operator

On Tue, Aug 06, 2002 at 10:57:49PM -0500, Anthony Ritter wrote: > > I tried an example with the number 3 replacing the number 1 > $image_src=$image_dir. "/" .substr($counter, $i, 3) . ".jpg"; That's not what I'm talking about. I said "strlen($counter)", which determines the number of times the for loop itterates. Read the Control Structures section of the manual to see how for loops work. for($i=0; $i<strlen($counter); $i++) { $image_src=$image_dir. "/" .substr($counter, $i, 1) . ".jpg"; $image_tag_src.="<IMG SRC=\"$image_src\" BORDER=\"0\">"; } The short section of script you showed us makes me think you're working on a script that's going to display a graphical counter on your page. The reason that you're not seeing a difference between .= and = is because your counter is still below 10, so the length of $counter is 1, thus the loop only executes once. Bump the counter up to 10 and see what happens... The loop will execute twice and you'll get two image tags in the $image_tag_src variable. > However, in examples such as: > $a="This is a"; > $a.="test"; > echo $a; > // displays This is a test > There is a variable that has previously existed with a value > > In the script that I supplied, the variable: > $image_tag_src > did not hold any value until the line with the .= operator That's because the script is poorly programmed so it has a vulnerability, as mentioned in my earlier post. I assume you took this directly from the book you mentioned: "Beginning PHP4" by Wrox. Looks like we should steer people clear of that book in the future. Regardless, if a variable is set ahead of time or not, the value on the right gets appended to the existing value of the variable. When the variable isn't set yet, the value starting value is null and the new value gets tacked onto it. Enjoy, --Dan -- PHP classes that make web design easier SQL Solution | Layout Solution | Form Solution sqlsolution.info | layoutsolution.info | formsolution.info T H E A N A L Y S I S A N D S O L U T I O N S C O M P A N Y 4015 7 Av #4AJ, Brooklyn NY v: 718-854-0335 f: 718-854-0409