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PHP Variable into a number

Posted on 2016-10-15
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Last Modified: 2016-11-07
I'm having an issue with Less Than.  I am turning a variable into a number and evaluating it.
<?php
$percent = get_post_meta ($dt_grade_post_id, "marks-obtained-percent", true);
                                            $per = (int)$percent;
                                            if($per <= 89) {

								$user_option_alt = '<a href="'.get_permalink($quiz_id).'" class="dt-sc-button small">'.__('Retake Quiz', 'dt_themes').'</a>';
						
                                                       
                                                       } 

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in my code $percent  = 90.  No matter what it always passes the valuation.  Wjhat am I doing wrong?
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Question by:rgranlund
3 Comments
 
LVL 35

Expert Comment

by:Terry Woods
ID: 41845324
Try adding some debugging and see what you get:
<?php
$percent = get_post_meta ($dt_grade_post_id, "marks-obtained-percent", true);
                                            $per = (int)$percent;
die("percent: '$percent', per: '$per'");  # add this line
                                            if($per <= 89) {

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1
 
LVL 51

Accepted Solution

by:
Julian Hansen earned 500 total points
ID: 41845402
I replicated your code here works as expected.

wp_postmeta record
ss76.jpgSource
<?php
define('WP_USE_THEMES', false);
require('../wp-blog-header.php');

$dt_grade_post_id = 999;
$percent = get_post_meta ($dt_grade_post_id, "marks-obtained-percent", true);
$per = (int)$percent;
$user_option_alt = '';
if($per <= 89) {
  $user_option_alt = '<a href="'.get_permalink($quiz_id).'" class="dt-sc-button small">'.__('Retake Quiz', 'dt_themes').'</a>';
} 
echo "Result: [{$user_option_alt}]<br/>";

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Problem is somewhere else.
0
 
LVL 108

Expert Comment

by:Ray Paseur
ID: 41845429
Var_export() is your friend.  So is the error_log().  You can use these functions together.  They will let you capture a "moment in time" representation of the contents of your variables, and write that information into a log file that you can inspect after the fact.  You might use something like this:
$xxx = var_export($percent, TRUE);
error_log($xxx);

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But that said, one usual range of percentages is from 0 to 100, which translates to a two-digit decimal fraction expressing a value between 0.00 and 1.00.  When you cast these fractional values to integers, you may get unexpected results.
http://php.net/manual/en/language.types.integer.php

Here's how I would handle the issue...

1. Insert the data visualization code and check the error log to be sure you're working with the correct numeric values.
2. Run this little script to see how (int) casting works, then consider whether you want to use casting or the more mainstream approach of round().  Or if you're preparing a number for visual display, number_format() is often useful.
<?php // demo/temp_rgranlund.php
/**
 * https://www.experts-exchange.com/questions/28976679/PHP-Variable-into-a-number.html
 *
 * http://php.net/manual/en/language.types.integer.php
 */
error_reporting(E_ALL);

$questions = 100;
$correct   = 89.999;
$percent   = ($correct / $questions) * 100;
$integer   = (int)$percent;

echo PHP_EOL . "PERCENT $percent IS CAST TO INTEGER $integer";

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Outputs:
PERCENT 89.999 IS CAST TO INTEGER 89

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