|
PHP - Using Arithmetic Operators To Define A For Loop...
Hello
I'm trying to use PHP "for loops" to build a table of 10 rows with 5 columns and I'm sure there's a better way to do this, but the result is the page won't fully load and continually spins its wheel. Here's the code: Code: [Select] $states = array(1 => 'AK','AL','AR','AZ','CA','CO','CT','DC','DE','FL','GA','HI','IA','ID','IL','IN','KS','KY','LA','MA','MD','ME','MI','MN','MO','MS','MT','NC','ND','NE','NH','NJ','NM','NV','NY','OH','OK','OR','OZ','PA','PR','RI','SC','SD','TN','TX','UT','VA','VT','WA','WI' ); <table id="stateCheck"> <?php for ($i = 1; $i <= 10; $i++) { echo '<tr>'; for ($j = 5*$i; $j <= $j+4; $j++) { echo '<td> <input type="checkbox" name="state" value="'.$states[$j].'" /> '.$states[$j].' </td>'; } echo '</tr>'; } ?> <tr> <td> <input type="checkbox" name="state" value="WV" /> WV </td> <td> <input type="checkbox" name="state" value="WY" /> WY </td> </tr> </table> Is it breaking because I'm using arithmetic operators to define the nested for loop? Many thanks Similar TutorialsI am trying to add foo onto bar inside a loop so I can then echo bar outside the loop and see the sum. The PHP manual doesn't have anything on addition in the way I need it (adding onto), so I was wondering if anyone can help me? LOL embrace yourself! $query = "select * from products where id='{$content['id']}'"; $result = mysql_query($query); $row = mysql_fetch_array($result); mysql_query ($query); mysql_close($link); echo " <B>Product ID:</B> {$content['id']} <BR> <B>Price:</B> $row[price] AUD <BR> <BR> "; +$row[price] -> $total; } echo $total; So I added a number unformatted and got the expected value, but after I formatted it I received an incorrect value? The Number unformatted looks like this: 441492111.66667. So did $number + 10 and got = 441492121.66667. That's all fine and correct. But after I formatted like so: $final = number_format($number) + 10; I got 451. Not too sure why that would happen, can someone explain to me please? Hello again. I run a sports league website and registrations received after a certain date need to have their league fees calculated to add 10%. someone wrote this for me a couple of years ago, but I have since then lost the full code. Need to know how to add a date to the follow statement that would automatically add the 10%. Can someone look at this for me and fill me in on what's missing? Thanks! Code: [Select] /* * Calculate fees */ $intSize = intval($arrLeagueSearch['size']); switch($intSize) { case 2: $dblBase = 150.00; $intBSize = 3; break; case 4: $dblBase = 330.00; $intBSize = 6; break; case 6: $dblBase = 550.00; $intBSize = 10; break; default: die("Invalid league size"); }; $dblEarlyTeam = $dblBase; $dblEach = $dblEarlyTeam / $intPlayers; /* $dblLateTeam = $dblEarlyTeam * 1.10; $dblLateEach = $dblLateTeam / $intPlayers; */ Hi all, I was reading a bit in the manual about the defined function. Since i have seen it being used quite a lot to disallow direct access. But one of the comments made me think if there are any alternatives to get the same. it's this comment: http://www.php.net/manual/en/function.defined.php#89886 If i read it correct it tells that defined() seems to be pretty slow. I was thinking, if that is the case what are the alternatives... Does anyone know how to interpret this comment and if there are alternatives? I am not yet a guru tofully understand the results. cheers! In many cases, variable have to be explicitly defined for whatever reason. However, often it is not required for a simple web page script. Yet, even in those cases, if a variable is NOT explicitly defined, the web server error log (example: my_domain.com-error_log) will rack up a lot of entries such as this: Quote [Fri Dec 31 01:31:43 2010] [error] [client 123.123.123.123] PHP Notice: Undefined variable: some_variable_name in /home/my_domain/public_html/some_page.php on line 6 A busy site could result in large error logs... What is considered "best practice"? Should all variables always be explicitly defined with the var key word? Hi guys! I am trying to understand why the final value of $m equals 40 in the following code Code: [Select] <?php $i = 29; $j = 11; $m = 10; $j = ($j - 4) / 2; $m += $j * 10; echo "m = ".$m."<br>"; //Equals 40 ?> Can anyone explain me please? I feel very confused right now. I came across these pieces of code and have been trying to understand this operator -> Or if it is a operator. I have searched and couldn't find explanations. In trying to learn I need to know what is is used for. Is it used only with classes? $m->myMethod(); return $this->x; Hi every one, I just want to know what is the use of '<<' and '>>' operators in php I'm trying to get an equation from a user that types it in the url, ex) 1+2+3. I can get the 1,2,3 fine, but the + operator is no longer in the string. Same with the * and / operators. Is there a way to keep them as a string using $_GET?
I have a query that is very messy. I have tried using () to seperate everything and when I do it just all goes wrong. here is the query SELECT posts.*, users.*, countries.countryID, countries.country FROM posts INNER JOIN users ON users.userID = posts.postUserID INNER JOIN countries ON countries.countryID = users.userCountry WHERE posts.cityID = '".$row_rs_city['cityID']."' AND posts.type = 'sightseeing' OR posts.cityID = '".$row_rs_city['cityID']."' AND posts.type = 'Inner city sightseeing' OR posts.cityID = '".$row_rs_city['cityID']."' AND posts.type = 'Outer city sightseeing' ORDER BY posts.postID DESC Is there a way of re-writing this so that it has brackets seperating everything and it will still work. It works for the minute but re- writing posts.cityID = '".$row_rs_city['cityID']."' inbetween every OR just seems wrong. Thanks for your help guys i'm trying to develop a deeper understanding of sessions, and I found this article on php.net regarding sessions with the following script;
<?php
// Get the private context
session_name('Private');
session_start();
$private_id = session_id();
$b = $_SESSION['pr_key'];
session_write_close();
// Get the global context
session_name('Global');
session_id('TEST');
session_start();
$a = $_SESSION['key'];
session_write_close();
// Work & modify the global & private context (be ware of changing the global context!)
?>
<html>
<body>
<h1>Test 2: Global Count is: <?=++$a?></h1>
<h1>Test 2: Your Count is: <?=++$b?></h1>
<h1>Private ID is <?=$private_id?></h1>
<h1>Gloabl ID is <?=session_id()?></h1>
<pre>
<?php print_r($_SESSION); ?>
</pre>
</body>
</html>
<?php
// Store it back
session_name('Private');
session_id($private_id);
session_start();
$_SESSION['pr_key'] = $b;
session_write_close();
session_name('Global');
session_id('TEST');
session_start();
$_SESSION['key']=$a;
session_write_close();
?>
[EDIT BY danbrown AT php DOT net: Contains a bugfix provided by (lveillette AT silexmultimedia DOT com) on 19-NOV-09.]
I do not understand line 21 and 22.
<h1>Test 2: Global Count is:<?=++$a?></h1>If I change this to; <h1>Test 2: Global Count is:<?php echo =++$a; ?></h1> or <h1>Test 2: Global Count is:<?php =++$a ?></h1>I would get a parse error, unexpected "=" in line 21. Can anyone explain why this is? * Why is it being echoed * Why can I not use echo in this case * Why does the code not start with <?php ? * What does line 21 even mean? =++$a? Thanks in advance guys! Edited by empec, 13 July 2014 - 11:30 AM. In php is there a way to shortcut logical operators... example: Code: [Select] if ($row['CustomerSaas'] == 'Yes' && ($row['CustomerSaasPaidStatus'] == 'Trial' || $row['CustomerSaasPaidStatus'] == 'Trial Ended')) { to Code: [Select] if ($row['CustomerSaas'] == 'Yes' && ($row['CustomerSaasPaidStatus'] == 'Trial' || 'Trial Ended')) { hi everyone
i keep seeing the following Comparison Operators:
<>i see it used in the following context:
if ($connection <> 'SSL')
{
$connection = 'NONSSL';
}
be grateful if somone would tell me what it means, i looked online but could not find the symbol
thanks
While going through an instructional book, I ran across some code that I didn't immediately understand. I've stripped it down to the relevant bits: function example($object_a, $object_b) { $compare = $object_a->id == $object_b->id; return another_function('argument 1') && $compare || another_function('argument 2'); } My first confusion was this line: $compare = $object_a->id == $object_b->id; Does this set $compare to TRUE if the ids match and FALSE if they do not? And the second confusion: return another_function('argument 1') && $compare || another_function('argument 2'); What is returned if the ids match? What is returned if they are different? When I try testing this out on my machine, it returns both functions whether or not the ids match, but I know that's not what's supposed to happen. Can anyone break this down for me? Thanks. Hello. Im having trouble using a Tempory Operator in a list. maybe someone might know a way around it. so the list below has 3 Tempory Operators. the first 1 looks for pages with links that are internal links the first 2 looks for pages with links that are external links the first 3 looks for pages with links that have no links if the link is a "nonTitle" it will be a normal list item if the link is a "title" it will be a header for a sub list (class="subexpandable") the problem is that every time it gets to the '; at the end of each Tempory Operators it breaks THIS IS NOT WORKING Code: [Select] <ul> //FIND INTERNAL LINKS echo $type == "internal" && $list == "nonTitle" ? '<li><a href="index.php">'.$title.'</a></li>' : '<li><a href="index.php" class="subexpandable">'.$title.'</a>'; //FIND EXTERNAL LINKS echo $type == "external" && $list == "nonTitle" ? '<li><a href="http://www.url.com">'.$title.'</a></li>' : '<li><a href="http://www.url.com" class="subexpandable">'.$title.'</a>'; //FIND NON LINKS echo $type == "non" && $list == "nonTitle" ? '<li><a>'.$title.'</a></li>' : '<li><a class="subexpandable">'.$title.'</a>'; //GET SUB LINKS echo' <ul class="subcategoryitems" style="margin-left: 15px"> <li><a href="">sub link</a></li> </ul> </li> </ul>'; If i put the sub level inside of each type it works but then i keep having to use the same code over. THIS IS WORKING Code: [Select] <ul> //FIND INTERNAL LINKS echo $type == "internal" && $list == "nonTitle" ? '<li><a href="index.php">'.$title.'</a></li>' : '<li><a href="index.php" class="subexpandable">'.$title.'</a> <ul class="subcategoryitems" style="margin-left: 15px"> <li><a href="">sub link</a></li> </ul> </li>'; //FIND EXTERNAL LINKS echo $type == "external" && $list == "nonTitle" ? '<li><a href="http://www.url.com">'.$title.'</a></li>' : '<li><a href="http://www.url.com" class="subexpandable">'.$title.'</a> <ul class="subcategoryitems" style="margin-left: 15px"> <li><a href="">sub link</a></li> </ul> </li>'; //FIND NON LINKS echo $type == "non" && $list == "nonTitle" ? '<li><a>'.$title.'</a></li>' : '<li><a class="subexpandable">'.$title.'</a> <ul class="subcategoryitems" style="margin-left: 15px"> <li><a href="">sub link</a></li> </ul> </li>'; </ul>'; so is there a way to do the first example without having to do the second example thanks ricky I was looking at the manual:
http://php.net/manua....precedence.php
And I notice that the parenthesis () operator and print operator are missing from the list. Why so? I would like to know where these operators fall in the precedence and associativity chart.
Here is a simple script which uses bitwise operations to determine whether or not a checkbox has been set. The problem is that if you use the $alpha array, the script doesn't produce the results you should expect. For example, if you set the last checkbox while using the $alpha array, all the checkboxes become set. I partially know why this happens as the PHP-Manual enlightened me: Quote From: http://www.php.net/manual/en/language.operators.bitwise.php Don't right shift for more than 32 bits on 32 bits systems. Don't left shift in case it results to number longer than 32 bits. I attempted to use the GMP_* functions but because those aren't part of the PHP-Standard-Library, I do not wish to rely on them. Is there any way to make these functions work for integers beyond 2^31? Here is a standalone script I'm using to make these tests. $alpha = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'); $delta = range('a', 'z'); function generate($array){ $n = count($array); $c = array(); for($i = 0; $i < $n; ++$i){ $c[bcpow(2, $i)] = $array[$i]; } return $c; } function set($array, $post){ $c = 0; foreach($array as $key => $val) if(isset($post['c'.$key])) $c |= $key; return $c; } function check($num, $category){ if($num & $category) return 'CHECKED'; return ''; } function checkboxes($array, $numval=0){ $i = 0; $form = ''; foreach($array as $key => $val){ $checked = check($numval, $key); $form .= '<input type="checkbox" '.$checked.' name="c'.$key.'" id="c'.$key.'">' . '<label for="c'.$key.'"> '.$val.'</label><br />'; ++$i; } return $form; } $array = generate($alpha); $num = 0; if(isset($_POST['action'])){ $num = set($array, $_POST); echo $num; } echo '<form action="y.php" method="post" style="width: 400px; border: 1px solid black;">'; echo checkboxes($array, $num); echo '<input type="submit" name="action" value="Set" />'; echo '</form>'; Can someone help me understand parentheses structure? Why here does the second empty() have no parentheses before it and an extra parentheses at the end? if (empty($subject) && empty($text)) { .... And here, why is there an extra parentheses at the end? if (empty($subject) && (!empty($text))) { ... And here, why double parentheses in the 1st empty() and none before the 2nd empty() ? if ((!empty($subject)) && empty($text)) { ... Thank You! michael I'm using the following code. I have tried placing parenthesis around $date1 and $date2 to separate them. No matter where I place the parenthesis Dreamweaver keeps giving me a syntax error. If I remove the second operator $date2 with the && the error goes. checked all my books but I can't see what is probably a stupid error ! Code: [Select] if ($row_sales_shipping_tax['cdate'] >= $date1 && <=$date2 ) Thanks for the help ! Hi all, Is it possible in php to read data from file as binary and operate on it with bitwise operators and save result as binary. Thanks |
|||||||