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PHP - Evaluating Math Formulas
Hey.
So imagine this example...
class FormulaEvaluator {
...... //Construct & variables here..
public function exec() {
//Missing some lines here, but you get the idea
$formula = $this->formula;
$context = (array) $this;
ob_start();
$res = eval('return ' . $formula . ';');
}
}
$formulaEvaluator = new FormulaEvaluator();
$formula = '10 * (($Test * 2) + ($Test2 / 3))';
$formulaEvaluator->formula = $formula;
$formulaEvaluator->Test = 20000;
$formulaEvaluator->Test2 = 300000;
$res = $formulaEvaluator->exec();
echo $res; //1400000
The code we have is working as intended, but we want to avoid using eval. I know it's a pretty common question, and the answer is usually the same, but is there any way to do something similar without using eval?
Similar TutorialsWith this code, I am trying to create a guessing game. When I press the START button, I want it display a guess, highest, and the lowest number between 1-100. The highest number being 100, and the lowest being 1. I'm trying to get the math formula to do this equation (Guess = round((Highest +Lowest))/2. Can any one give me a hand. Code: [Select] <head> <title> Project 3 </title> </head> <body> <h1>Guessing Game</h1> <form method='post' action=''> <input type='submit' name='start' id='start' value='Start Game'> <form method='post' action=''> <input type='submit' name='higher' id='higher' value='Higher'> <form method='post' action=''> <input type='submit' name='lower' id='lower' value='Lower'> <?php if (isset($_POST['start'])) { print"<input type = 'hidden' name = 'hdnCount' value = '$count'> <input type = 'hidden' name = 'hdntop' value = '$top'> <input type = 'hidden' name = 'hdnbottom' value = '$bottom'> <input type = 'hidden' name = 'hdnguess' value = '$guess'>"; } if (isset($_POST['higher'])) { $count = $_REQUEST["hdnCount"]; $top = $_REQUEST["hdntop"]; $bottom = $_REQUEST["hdnbottom"]; $guess = $_REQUEST["hdnguess"]; print" <input type = 'hidden' name = 'hdnCount' value = '$count'> <input type = 'hidden' name = 'hdntop' value = '$top'> <input type = 'hidden' name = 'hdnbottom' value = '$bottom'> <input type = 'hidden' name = 'hdnguess' value = '$guess'>"; } if (isset($_POST['lower'])) { $count = $_REQUEST["hdnCount"]; $top = $_REQUEST["hdntop"]; $bottom = $_REQUEST["hdnbottom"]; $guess = $_REQUEST["hdnguess"]; print" <input type = 'hidden' name = 'hdnCount' value = '$count'> <input type = 'hidden' name = 'hdntop' value = '$top'> <input type = 'hidden' name = 'hdnbottom' value = '$bottom'> <input type = 'hidden' name = 'hdnguess' value = '$guess'>"; } ?> </form> </body> </html> Hello I would like to know how to parser chemical and mathematical formulas into images or html-based layout. Please advise me. Thank you. Hi all, I've stored a formula in a mysql db table that is pretty basic. To give an example: Code: [Select] IF(x=1) { y = 2; } IF(x=2) { y = 3; } IF(x>2) { y = 0; } x represents the value from the input field from while y represents the output value (that will be shown through a span element innerHTML). My question is, how can I firstly retrieve this formula from the table and then secondly adapt the x as the value from the input field and then show the result as the output? Thanks I'm using Paypal Shopmaker for an online store. It is all in PHP. I'm not much of a programmer - especially not PHP. I'd like to change the contents of the confirmation email a customer is sent for one product only. Here is the original code that puts the text into the email: } else { // Send notification email directly ewpp_LoadEmail("ipn.txt"); I'd like to test the Item array for the special product and put different text into the email. This is what I thought of: } else { // Send notification email directly // Add check for Total Sondheim Package if ($ewpp_Item["ItemName"]=="Total Sondheim Seminar Package") { ewpp_LoadEmail("ipn_total_sondheim.txt"); } else { ewpp_LoadEmail("ipn.txt"); } Do you think that might work? Or this? foreach ($arrCart as $cartItem) { if ($cartItem["item_name"] == "Total Sondheim Seminar Package") { ewpp_LoadEmail("ipn_total_sondheim.txt"); } } else { ewpp_LoadEmail("ipn.txt"); } Any help you can offer would be greatly appreciated. Stephen Stephen Hi, Apologies if this is rather easy but wondered how you would get around the following problem. I have a post being sent on a checked form that has the name set to a value used in my DB, for example: Code: [Select] <input type="checkbox" name="<?PHP echo $rows ["catID"] ?>"> Where name would equal something like 11. I'm trying to right some code that inserts data from the rows that have been checked, bit like the below: Code: [Select] while($rows = $database->fetch_array($result)){ $strSQL='INSERT INTO affiliate_join_cat (ajcCatID, ajcAffID) VALUES ('.$rows["catID"].', '.$_POST["affID"].')'; if ($_POST($rows["catID"])=="on"){ $database->query($strSQL); so my post will look something like 11 = on, dependent on the row checked. But there is something wrong with this part of the code: Code: [Select] $_POST($rows["catID"])=="on" my thoughts are that until catID actually equals 11 this does not evaluate to anything? So have tried using empty and isset to handle it without any success. Not sure what to do next? Thanks in advance Hi guys. I'm using php to randomly generate a simple math verification question. But, I'm having a hard time validating the input. Can someone please tell me what I'm doing wrong? Thank you } else if(trim($verify) != $_SESSION['UserData']['Math'][0]+$_SESSION['UserData']['Math'][1]){ $error = '<div class="error_message">Attention! The verification number you entered is incorrect.</div>'; } <?php echo "<span class='label'><span class='required'>*</span>What is ".$_SESSION['UserData']['Math'][0]." + ".$_SESSION['UserData']['Math'][1]."?</span> "; ?> <input name="verify" type="text" id="verify" size="3" value="<?=$verify;?>" /><br /><br /> Hi, I am TheMeq. I am currently developing a Text-Based MMORPG in PHP/MySQL. I have quite alot of the code laid down, its just this bit that is starting to throw me a bit. I've been working on it since 8am this morning.. it is now 4:30pm and i think it's nearly there. It's just not working the way I would like. So if I was to ask for help, should I just post what code I have? Trying to get the percentage of rent for a property in php. Im completely lost .... Code: [Select] <?php $purchase = 44000; $rent = 9860; $percent = $purchase * $rent; //this is wrong, it returns 4.3 but should be over 18 echo "Percentage is {$percent}%"; ?> is there a math function that give you an integer value when u divide 2 numbers? ie in 7/3 i just want 2 as a result not floating number. thanks in advance. Hello Everyone, I'm a newbie trying to improve my script below. The script works fine but I would like to add the 3 radio buttons computations enhancements Ergo, if a user chooses 'Matte Paper" a 10% would be added to the Price Quote result. If a user chooses ' Gloss Paper, a 10% would be added to the Price Quote result. If a user chooses 'Canvas" , a 20 % would be added to the Price Quote result. If someone could assist with the math or post me a helpful link it would be greatly appreciated. Thank you. Paul from Melbourne, Australia. <div style="border:dashed 1px; width:570px;"> <form method="post" action="<?php echo $_SERVER['php_SELF'];?>"> <p> 1. Enter the size (100w.x180h. cm) you want your picture printed: Width <input type="text" name="width" size="1" maxlength="3" value="0" onFocus="this.value=''; this.style.color='#ff0000';"> Height <input type="text" name="height" size="1" value="0" maxlength="3" value="0" onFocus="this.value=''; this.style.color='#ff0000';"> </p> <p> 2. Choose the printing material for your pictu <input type="radio" value="cms in Matte paper" name="material" size="3" maxlength="3" /> Matte Paper <input type="radio" value="cms in Gloss Paper:" name="material" size="3" maxlength="3" /> Gloss Paper <input type="radio" value="cms in Canvas:" name="material" size="3" maxlength="3" /> Canvas </p> <p> 3. Submit your info for our Price Quote below : <input type="submit" name="submit" value="Submit" /> or: <input type="submit" name="clear" value="Reset" /> </p> <p> 5. Our Price Quote to print your artwork sized: <?php $width = $_POST['width']; /* if artwork wider than 101 cm no quote, exits*/ if ($width >=101) {echo "Error!"; exit ;} $height = $_POST['height']; /* if artwork higher than 181 cm no quote, script exits */ if ($height >=181) {echo "Error!"; exit ;} $measurement = $_POST['measurement']; $material = $_POST['material']; $result = $width * $height; echo " $width x $height $material is: "; echo "$".number_format($result,2). "" ; ?> </p> </form> </div> I'm trying to make a script to check a files date time and if its under so many seconds long the page will refresh. here is what I've got. I've been testing the output of the date() functions but when i do the math all i get is a 0. where did i go wrong? is it just i can't do math with dates? Thanks in advanced. Code: [Select] <html><head> <meta http-Equiv="Cache-Control" Content="no-cache"> <meta http-Equiv="Pragma" Content="no-cache"> <meta http-Equiv="Expires" Content="0"> <? $proFile = "profilePics/profile.jpg"; //if ( date ("m d Y H:i:s.") - date ("m d Y H:i:s.", filemtime($proFile)) <= 00 00 0000 00:00:04 ){ //this is where the magic should happen. //echo "<meta http-equiv="refresh" content='4'>"; } ?> </head> <? echo date ("m d Y H:i:s."); echo "<br>"; echo date ("m d Y H:i:s.", filemtime($proFile)); echo "<br>"; echo date ("m d Y H:i:s.") - date ("m d Y H:i:s.", filemtime($proFile)); //only outputs 0 ?> I am trying to create a math equation inside a variable but I am struggling to achieve the desired result. On one php page I have this:
$x = "date('Y')"; On my main page I have linked to the above and also $description but the result I am getting is: In this classic lecture which was delivered over date('Y') - 1989 years ago,
I want to create a variable so I don't need to go back every year and change the description. Is this possible? Robert
Hi guys, I just decided to add an addition question in my site for submitting a form, not gonna say where coz one of you will most proberly try to prove it doesnt work! I have a feeling its easy enough for someone to send my form by getting the two variables and evaluating them. But how would they do that? and how would they know the names of the variables to send...? Is there a way of doing a math captcha that cannot be hacked? This topic has been moved to PHP Math Help. http://www.phpfreaks.com/forums/index.php?topic=357542.0 The title may not fit but only thing i could think of. I am pulling data from MSSQL database table.... I need everything from that table but i need to do some basic math funcitons to the resulting data. So the quesiton is should i do the math for this in the SQL query if so how do i pull all fields and do the math in an effcient way. Or should i let php do the math for me after i get all the data i need. If it is better to use php how can i do this in a while loop and get the math result and not a printed equation. Just looking for a few pointers never had to do math before with php Please deal with me for a moment as I try to explain what is occurring. I have created drop down menu that you choose a name and the php/MySQL will run multiple queries to display information regarding the chosen name. The query works great. There is no problem with the query. However when you leave the page, either by navigation or by X'ing out. When you return there are two errors that pop up: Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in You can then use the drop down menu and choose a name and it all works great. It is my belief that these errors occur due to how the query was written, as the two queries that have these errors both have math in them. My question is, how do I block these errors from occurring when you return to the page? Here is the query: <?php //Worst Regular Season Record include_once('../other/functions.php'); $con = mysql_connect($hostname, $username, $password) OR DIE ('Unable to connect to database! Please try again later.'); $db = mysql_select_db($dbname, $con); $query = "SELECT win, loss, year, teamname FROM standings, owners WHERE owners.owner_id = standings.owner_id AND win = (SELECT MIN(win) FROM standings) AND standings.owner_id = $thing ORDER BY year"; $result = mysql_query($query); $row = mysql_fetch_array($result); @ mysql_data_seek($result, 0); if(mysql_num_rows($result)>0) { echo "<table CELLPADDING=5 border =1>"; echo "<tr>"; echo "<th align=center colspan=4 > Worst Regular Season Record </th>"; echo "</tr>"; while ($row = mysql_fetch_array($result)) { echo "<tr>"; echo '<td align=center> In '.$row['year'].', the '.$row['teamname'].' had '.$row['win'].' wins, and '.$row['loss'].' losses.</td>'; echo "</tr>"; } } else { } echo "</table>"; mysql_close($con); ?> I can' t even get the simple str_replace to work. I got.... $rslt = $client->getTodaySubIDStats($key, $sub_id); $rslt = str_replace("EARNINGS",'',$rslt); $rslt = str_replace("Array","",$rslt); $rslt = str_replace("\r","",$rslt); $rslt = str_replace("\n","",$rslt); $rslt = str_replace("\t","",$rslt); print_r($rslt); which spits out.... Code: [Select] Array ( [0] => Array ( [EARNINGS] => $100.40 [CLICKS] => 1301 [LEADS] => 100 [SUB_ID] => yacker [EPC] => $0.11 ) ) I would like to have every thing removed except the '$100.40' (The number is always changing). Then remove the $ and do math 100.40*.40, so in the end, all it spits out is 40.16 and always only have two digits after the period. Having to go into somebody else's code yet again! Gah! Originally the totaling page just subtracted a flat discount. But now the client wants to be able to subtract percentage discounts and 'per item' discounts. In the discount table I added a field to determine whether the discount chosen is to be applied as flat off total, flat per item, % off total, and % off each item. I also entered a field that can have a class id, in case this discount is only for that class. (the intention being that otherwise the discount is on anything) I've got a session variable that generates something like : Array ( [217] => 1 [215] => 2 ) meaning 1 person in class #217, and 2 people in class 215. $_SESSION['s_to_be_added'] = array_filter($_POST['participantqty']); Then on the page I'm concerned with, I've been trying to write the script. I know I still need some math stuff figured out But how do I take the array, do the math, and then generate an overall cost for the whole thing? and this is just the discounting? I don't even have a clue how to work in delimiting it if there's a class id.. did any of that make sense? Code: [Select] <?php // the above is the array I want to use to $passed_array = array_filter($_SESSION['s_to_be_added']); // this is the discount 'code' the user entered. $discount = mysql_escape_string($_POST['discount']); // just a donation added after everything. $donation = mysql_escape_string($_POST['donation']); // finding the discount that matches the discount 'code' entered. $query_selectAllItems_events = "SELECT discount_amount,discount_type,workshop_link_1 FROM tbl_discount where discount_value = '$discount'"; $result_all_events = mysql_query($query_selectAllItems_events); $numRows_all_events = mysql_num_rows($result_all_events); $num=mysql_num_rows($result_all_events); $z_row = mysql_fetch_array($result_all_events); // this is just a number: 1, 20, 90 etc. $discount_amount = $z_row['discount_amount']; /*this is 1,2,3,4 - for each type of discount 1- flat 2- flat per item 3- discount on all, 4- discount per item */ $discount_type = $z_row['discount_type']; // the workshop id if the discount is onlyh for this workshop $discount_link_1 = $z_row['workshop_link_1']; // just a description $discount_name = $z_row['discount_name']; if ($discount_type ==1) { /* flat discount on total here */ $total = mysql_escape_string($_POST['total']); $final_total = ($total - $discount_amount); $final_total = ($final_total + $donation); } elseif ($discount_type ==2)) { /* discount per item total here */ $total = mysql_escape_string($_POST['total']); $final_total = ($total - $discount_amount); $final_total = ($final_total + $donation); } elseif ($discount_type ==3)) { /* percentage discount on total here */ $total = mysql_escape_string($_POST['total']); $final_total = ($total * ($discount_amount/100)); $final_total = ($final_total + $donation); } elseif ($discount_type ==4)) { /* percentage discount per item here */ $total = mysql_escape_string($_POST['total']); $final_total = ($total * ($discount_amount/100)); $final_total = ($final_total + $donation); } ?> Code: [Select] if ($user['amount'] >= 15.00){ $user['max_stars'] = 3; } Ok and Code: [Select] if ($user['amount'] >= 20.00){ $user['max_stars'] = 4; }How can I write a function that will loop through the 15,20,25,30,35, all the way up to 600$ or if the max_Stars get's up to 80? I really don't want to have 80 if functions in my code :\ Hi guys! Am trying to get hold of a PHP Math Expression Parser that follows correct precedence and executes custom functions. Can somebody share his scripts? or lead me to the right directions? Hope you can help! Thanks a lot! My boss is gonna kill me soon. This is 1 week overdue already. Jon |
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