PHP Font Color
Yo, it's me again...lol. This time, I have a script that finds out if the primary key of a dB is even or odd, and then is supposed to select a font color based on this. It always seems to go with the ' != ' option, even when reverse the statements. What's wrong with this?
<?php
while ($qry = mysql_fetch_array($sql)) {
$date = $qry['date'];
$order = $qry['order'];
if (($order/2) = (round($order/2))) {
$font = \"p class=\\"sideright\\"\";
} elseif (($order/2) != (round($order/2))) {
$font = \"p class=\\"sideright2\\"\";
};
?>...later in the code, the color tag...
<td class=\"sideright\"><$font>$date:</td>Thanks.
Suzanne posted this at 02:32 — 5th February 2004.
She has: 5,507 posts
Joined: Feb 2000
http://www.linux.org.za/Lists-Archives/dev-0303/msg00019.html may work better for you. Testing evenness or oddness instead of rounding?
kb posted this at 04:07 — 5th February 2004.
He has: 1,380 posts
Joined: Feb 2002
But if an even # is divisible by 2(which it is)...then when i divide and compare to it's divided and rounded counterpart, why doesn't it work? (just curious)
Mark Hensler posted this at 04:10 — 5th February 2004.
He has: 4,048 posts
Joined: Aug 2000
I'm not sure, but it may be because your comparing a float to an integet (2.5~3).
Suzanne posted this at 15:55 — 5th February 2004.
She has: 5,507 posts
Joined: Feb 2000
Most likely it's failing because you're testing things wrongly -- x = y sets x equal to y. x == y tests if x and y are the same. The first (true) conditional statement doesn't make sense, the second does (false), so it defaults to the one that makes sense.
However, that said, it's not an efficient test of evenness/oddness because it requires too many mathematical computations. The function suggested in the thread I linked to is a smoother, likely faster, solution.
druagord posted this at 17:03 — 5th February 2004.
He has: 335 posts
Joined: May 2003
the easy way to find an odd number is to use modulo 2 like this
<?php
while ($qry = mysql_fetch_array($sql)) {
$date = $qry['date'];
$order = $qry['order'];
if (($order%2) == 0) {
$font = \"p class=\\"sideright\\"\";
} else {
$font = \"p class=\\"sideright2\\"\";
};
?>
IF , ELSE , WHILE isn't that what life is all about
Suzanne posted this at 17:53 — 5th February 2004.
She has: 5,507 posts
Joined: Feb 2000
That's what this guy has built his function around. I haven't had the need, but now that I know how, I'm thinking this would be interesting for colouring table rows?
<?php
// function: Check if a value ($value) is even or odd.
function even($value) {
if (is_int($value)) { // Per definition only integers can be odd/even
if (($value % 2) == 0)) { // Divide by 2 and if modulus is 0 we are even
return 1; // Number is even
} else {
return 0; // Number is odd
}
} else {
return 0; // Number is not an integer
}
}
?>
from: Carl Swart
druagord posted this at 17:59 — 5th February 2004.
He has: 335 posts
Joined: May 2003
it can be usefull for all kind of thing but your right thats how i use this most of the time. Sorry i didn't follow the link you put guess i was to eager to answer
IF , ELSE , WHILE isn't that what life is all about
Suzanne posted this at 18:01 — 5th February 2004.
She has: 5,507 posts
Joined: Feb 2000
No shame in being eager, heh. I thought to myself when you wrote that, well, hmmm, maybe I should post the whole function instead of just linking to it. Always thinking of the lurkers, that's me!
kb posted this at 00:40 — 6th February 2004.
He has: 1,380 posts
Joined: Feb 2002
I checked php.net for modulus, but it didn't help define it. What exactly is "modulus"?
Abhishek Reddy posted this at 00:50 — 6th February 2004.
He has: 3,348 posts
Joined: Jul 2001
"modulus" means "remainder of". If you have 4%2 or mod (4, 2) your result will be 0. That is, 4 divided by 2 is 2, with 0 remaining. Whereas if you had 3%2 or mod (3, 2) your result would be 0.5, since 3 divided by 2 is 1 plus a remainder of 0.5. So you can test for even numbers by looking for a returned value of 0 after using %2. Anything else should be odd.
Suzanne, modulus is the standard way of colouring tables, afaik. What have you been using, then?
Suzanne posted this at 14:19 — 6th February 2004.
She has: 5,507 posts
Joined: Feb 2000
I don't colour table rows, as a habit.
I haven't done anything (yet) that would require it (in php).
druagord posted this at 14:15 — 6th February 2004.
He has: 335 posts
Joined: May 2003
no 3/2 would give 1 reminder 1 so 3%2 would give 1 as a result. there are no decimals with modolus only integers. Try to remember the first division you made in school before you learned about decimals
15%10 would be 5
IF , ELSE , WHILE isn't that what life is all about
Suzanne posted this at 14:29 — 6th February 2004.
She has: 5,507 posts
Joined: Feb 2000
http://www.google.com/search?q=15%2510
Google is so handy! Don't mind me while I walk through this for my own edification:
10 gahzinta* 15 once, remainder 5
2 gahzinta 3 once, remainder 1
8 gahzinta 16 twice, remainder 0
2 gahzinta $anyevennumber exactly, remainder 0
So if it's even, it returns 0, no matter what.
Excellent.
Now, how you do you set it up? Oh, of course, since two goes into any even number perfectly, you'll always get a remainder of zero for %2 if the number is even.
Nifty!
These are all zero:
http://www.google.com/search?q=36895825420%252
http://www.google.com/search?q=2%252
http://www.google.com/search?q=18%252
*gahzinta = "goes into" slang slang slang
druagord posted this at 14:40 — 6th February 2004.
He has: 335 posts
Joined: May 2003
Another use of modulus i came across a few time is when displaying result in multiple pages. Let say i have 25 results per pages i do a query that comes up with 134 results i do
number of pages = ceil(134/25) = 6
number of result on the last page = 134%25 = 9
IF , ELSE , WHILE isn't that what life is all about
Abhishek Reddy posted this at 10:50 — 7th February 2004.
He has: 3,348 posts
Joined: Jul 2001
Hm, true, druagord. Guess I have to revisit my math.
I've used modulus in ASP to create evenly distributed results in three columns, similar to pagination. Very handy.
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