There is this function that is used tat I didn't myself create, but at the moment it is only returning the number rounded with 2 decimal places, but I want to change it so it returns it with three; however I don't really understand how it all works.
Here is the function:
function round_number($number, $round = 2)
{
// we will multiply by 10^$round, then get the floor value of that amount then divide by 10^round.
## -> if it does problems, switch back to floor()
$temp_value = $number * pow(10, $round);
$temp_value = (!strpos($temp_value, '.')) ? $temp_value : floor($temp_value);
$number = $temp_value / pow(10, $round);
return $number;
}
I assume if I change the $round to 3 that it will return correctly?
// we will multiply by 10^$round, then get the floor value of that amount then divide by 10^round.
## -> if it does problems, switch back to floor()
It says it right in the code what it does!
And yes - changing $round = 3; will work.
However DON'T you should instead just call the function
round_number(12345.12342423, 3);
the number passed in as second parameter (3) will override the $round=2 in the function ($round=2 is the 'default')
Related
I have this code
<?php echo round(0.572,2,PHP_ROUND_HALF_UP);?>
I want to round two decimals to half up, I expect a value as 0.58...
but the above code print 0.57
How can I do this?
if you expect 0,58 you don't have to use a "half round" but the ceil function
$v = 0.575;
echo ceil($v * 100) / 100; // show 0,58
The value 0.572 can not be rounded up to 0.58, because the third decimal, 2, is less than half (or 5). If you were doing round(0.575, 2, PHP_ROUND_HALF_UP) you would get 0.58. In this case 0.57 is the correct rounded value.
If you wish to always round up from the 3rd decimal, regardless of its value you could use ciel() instead, but it requires a little additional math. A simple function to demonstrate rounding up always would be...
function forceRoundUp($value, $decimals)
{
$ord = pow(10, $decimals);
return ceil($value * $ord) / $ord;
}
echo forceRoundUp(0.572, 2); // 0.58
echo forceRoundUp(0.57321, 4); // 0.5733
function round_up($value, $places)
{
$mult = pow(10, abs($places));
return $places < 0 ?
ceil($value / $mult) * $mult :
ceil($value * $mult) / $mult;
}
echo round_up(0.572,2);
Hope this will work for you!!
I am new at programing and I am trying to figure out how to write a variable correctly. To calculate the number for this variable I have to divide by 10 and if the result does not evenly divide, I need to add 1 on to it.
So for example, lets I have to divide 294 / 10, I would get 29.4. In this case I would want to add 1, which would set the variable to 30. But if I was dividing 200 by 10, I would not need to add 1 because it would be an even 20.
So currently I have the variable like this:
$total = $count / 10;
How would I adjust it to set correctly in cases that it does not even .0
It sounds like you're trying to round the value up. There's a built-in function for this purpose -- ceil().
From the function description:
Returns the next highest integer value by rounding up value if necessary
Usage:
$count = 294;
echo ceil($count / 10); // => 30
Make use of ceil() in PHP
$count=294;
$total = ceil($count / 10); // your variable $total now holds the value of 30
You want to use a function called ceil
$total = ceil($count / 10);
http://www.php.net/manual/en/function.ceil.php
$total = $count / 10;
if(!is_int($total)) {
$total = ceil($total);
}
else {
// if you want to make some actions if number is exactly .0
}
You can use ceil() function for this.
$total = $count / 10;
echo ceil($total);
For more details refer http://php.net/ceil
This question already has answers here:
Truncate float numbers with PHP
(14 answers)
Closed 11 months ago.
I need to round down a decimal in PHP to two decimal places so that:
49.955
becomes...
49.95
I have tried number_format, but this just rounds the value to 49.96. I cannot use substr because the number may be smaller (such as 7.950). I've been unable to find an answer to this so far.
Any help much appreciated.
This can work: floor($number * 100) / 100
Unfortunately, none of the previous answers (including the accepted one) works for all possible inputs.
1) sprintf('%1.'.$precision.'f', $val)
Fails with a precision of 2 : 14.239 should return 14.23 (but in this case returns 14.24).
2) floatval(substr($val, 0, strpos($val, '.') + $precision + 1))
Fails with a precision of 0 : 14 should return 14 (but in this case returns 1)
3) substr($val, 0, strrpos($val, '.', 0) + (1 + $precision))
Fails with a precision of 0 : -1 should return -1 (but in this case returns '-')
4) floor($val * pow(10, $precision)) / pow(10, $precision)
Although I used this one extensively, I recently discovered a flaw in it ; it fails for some values too. With a precision of 2 : 2.05 should return 2.05 (but in this case returns 2.04 !!)
So far the only way to pass all my tests is unfortunately to use string manipulation. My solution based on rationalboss one, is :
function floorDec($val, $precision = 2) {
if ($precision < 0) { $precision = 0; }
$numPointPosition = intval(strpos($val, '.'));
if ($numPointPosition === 0) { //$val is an integer
return $val;
}
return floatval(substr($val, 0, $numPointPosition + $precision + 1));
}
This function works with positive and negative numbers, as well as any precision needed.
Here is a nice function that does the trick without using string functions:
<?php
function floorp($val, $precision)
{
$mult = pow(10, $precision); // Can be cached in lookup table
return floor($val * $mult) / $mult;
}
print floorp(49.955, 2);
?>
An other option is to subtract a fraction before rounding:
function floorp($val, $precision)
{
$half = 0.5 / pow(10, $precision); // Can be cached in a lookup table
return round($val - $half, $precision);
}
I think there is quite a simple way to achieve this:
$rounded = bcdiv($val, 1, $precision);
Here is a working example. You need BCMath installed but I think it's normally bundled with a PHP installation. :) Here is the documentation.
function roundDown($decimal, $precision)
{
$sign = $decimal > 0 ? 1 : -1;
$base = pow(10, $precision);
return floor(abs($decimal) * $base) / $base * $sign;
}
// Examples
roundDown(49.955, 2); // output: 49.95
roundDown(-3.14159, 4); // output: -3.1415
roundDown(1000.000000019, 8); // output: 1000.00000001
This function works with positive and negative decimals at any precision.
Code example here: http://codepad.org/1jzXjE5L
Multiply your input by 100, floor() it, then divide the result by 100.
You can use bcdiv PHP function.
bcdiv(49.955, 1, 2)
Try the round() function
Like this: round($num, 2, PHP_ROUND_HALF_DOWN);
For anyone in need, I've used a little trick to overcome math functions malfunctioning, like for example floor or intval(9.7*100)=969 weird.
function floor_at_decimals($amount, $precision = 2)
{
$precise = pow(10, $precision);
return floor(($amount * $precise) + 0.1) / $precise;
}
So adding little amount (that will be floored anyways) fixes the issue somehow.
Use formatted output
sprintf("%1.2f",49.955) //49.95
DEMO
You can use:
$num = 49.9555;
echo substr($num, 0, strpos($num, '.') + 3);
function floorToPrecision($val, $precision = 2) {
return floor(round($val * pow(10, $precision), $precision)) / pow(10, $precision);
}
An alternative solution using regex which should work for all positive or negative numbers, whole or with decimals:
if (preg_match('/^-?(\d+\.?\d{1,2})\d*$/', $originalValue, $matches)){
$roundedValue = $matches[1];
} else {
throw new \Exception('Cannot round down properly '.$originalValue.' to two decimal places');
}
Based on #huysentruitw and #Alex answer, I came up with following function that should do the trick.
It pass all tests given in Alex's answer (as why this is not possible) and build upon huysentruitw's answer.
function trim_number($number, $decimalPlaces) {
$delta = (0 <=> $number) * (0.5 / pow(10, $decimalPlaces));
$result = round($number + $delta, $decimalPlaces);
return $result ?: 0; // get rid of negative zero
}
The key is to add or subtract delta based on original number sign, to support trimming also negative numbers.
Last thing is to get rid of negative zeros (-0) as that can be unwanted behaviour.
Link to "test" playground.
EDIT: bcdiv seems to be the way to go.
// round afterwards to cast 0.00 to 0
// set $divider to 1 when no division is required
round(bcdiv($number, $divider, $decimalPlaces), $decimalPlaces);
sprintf("%1.2f",49.955) //49.95
if you need to truncate decimals without rounding - this is not suitable, because it will work correctly until 49.955 at the end, if number is more eg 49.957 it will round to 49.96
It seems for me that Lght`s answer with floor is most universal.
Did you try round($val,2) ?
More information about the round() function
my question is: is there a good (common) algorithm to create numbers, which match well looking user understood numbers out of incomming (kind of random looking for a user) numbers.
i.e. you have an interval from
130'777.12 - 542'441.17.
But for the user you want to display something more ...say userfriendly, like:
130'000 - 550'000.
how can you do this for several dimensions?
an other example would be:
23.07 - 103.50 to 20 - 150
do you understand what i mean?
i should give some criteria as well:
the interval min and max should
include the given limits.
the "rounding" should be in a
granularity which reflects the
distance between min and max (meaning
in our second example 20 - 200
would be too coarse)
very much honor you'll earn if you know a native php function which can do this :-)
*update - 2011-02-21 *
I like the answer from #Ivan and so accepted it. Here is my solution so far:
maybe you can do it better. i am open for any proposals ;-).
/**
* formats a given float number to a well readable number for human beings
* #author helle + ivan + greg
* #param float $number
* #param boolean $min regulates wheter its the min or max of an interval
* #return integer
*/
function pretty_number($number, $min){
$orig = $number;
$digit_count = floor(log($number,10))+1; //capture count of digits in number (ignoring decimals)
switch($digit_count){
case 0: $number = 0; break;
case 1:
case 2: $number = round($number/10) * 10; break;
default: $number = round($number, (-1*($digit_count -2 )) ); break;
}
//be sure to include the interval borders
if($min == true && $number > $orig){
return pretty_number($orig - pow(10, $digit_count-2)/2, true);
}
if($min == false && $number < $orig){
return pretty_number($orig + pow(10, $digit_count-2)/2, false);
}
return $number;
}
I would use Log10 to find how "long" the number is and then round it up or down. Here's a quick and dirty example.
echo prettyFloor(23.07);//20
echo " - ";
echo prettyCeil(103.50);//110
echo prettyFloor(130777.12);//130000
echo " - ";
echo prettyCeil(542441.17);//550000
function prettyFloor($n)
{
$l = floor(log(abs($n),10))-1; // $l = how many digits we will have to nullify :)
if ($l<=0)
$l++;
if ($l>0)
$n=$n/(pow(10,$l)); //moving decimal point $l positions to the left eg(if $l=2 1234 => 12.34 )
$n=floor($n);
if ($l>0)
$n=$n*(pow(10,$l)); //moving decimal point $l positions to the right eg(if $l=2 12.3 => 1230 )
return $n;
}
function prettyCeil($n)
{
$l = floor(log(abs($n),10))-1;
if ($l<=0)
$l++;
if ($l>0)
$n=$n/(pow(10,$l));
$n=ceil($n);
if ($l>0)
$n=$n*(pow(10,$l));
return $n;
}
This example unfortunately will not convert 130 to 150. As both 130 and 150 have the same precision. Even thou for us, humans 150 looks a bit "rounder". In order to achieve such result I would recommend to use quinary system instead of decimal.
You can use php's round function which takes a parameter to specify the precision.
<?php
echo round(3.4); // 3
echo round(3.5); // 4
echo round(3.6); // 4
echo round(3.6, 0); // 4
echo round(1.95583, 2); // 1.96
echo round(1241757, -3); // 1242000
echo round(5.045, 2); // 5.05
echo round(5.055, 2); // 5.06
?>
The number_format() function handles "prettifying" numbers with arbitrary thousands/decimal characters and decimal places, but you'd have to split your ranges/strings into individual numbers, as number_formation only works on one number at a time.
The rounding portion would have to handled seperately as well.
I haven't seen ready algorithm or function for that. But it should be simple, based on string replacement (str_replace, preg_replace), number_format and round functions.
This actually is kind of a special case, that can be addressed with the following function:
function roundto($val, $toceil=false) {
$precision=2; // try 1, 2, 5, 10
$pow = floor(log($val, 10));
$mult = pow(10, $pow);
$a = $val/$mult*$precision;
if (!$toceil) $a-=0.5; else $a+=0.5;
return round($a)/$precision*$mult;
}
$v0=130777.12; $v1=542441.17;
echo number_format(roundto($v0, false), 0, '.', "'").' - '
.number_format(roundto($v1, true), 0, '.', "'").'<br/>';
$v0=23.07; $v1=103.50;
echo number_format(roundto($v0, false), 0, '.', "'").' - '
.number_format(roundto($v1, true), 0, '.', "'").'<br/>';
Outputs exactly this:
100'000 - 550'000
20 - 150
For any other case of number formatting it might be interesting to have a look at my newly published PHP class "php-beautiful-numbers", which I use in almost ever project to display run times ("98.4 µs" [= 9.8437291615846E-5]) or numbers in running text (e.g. "you booked two flights." [= 2]).
https://github.com/SirDagen/php-beautiful-numbers
A have price data stored like this: 10.25
And percentage data like this 1.1100 (1.00%)
I need a function that accurately multiplies the price by the percentage. (in php)
Thanks
You should never store currency as a decimal. Always use intergers.
What is wrong with $money * ($percentage / 100)
It would probably be best if you split the storage of your percent data into two different fields if possible. But this will do what you're looking for, I believe. I split it into two functions - "convertPercentageDataToDecimal" extracts the percent from your data and converts it to a decimal, then "convertPercentageDataToDecimal" simply multiplies the price by the percent.
<?php
$price = 10.25;
$percentageData = "1.1100 (1.00%)";
function multiplyPriceByPercentageData($price, $percentageData) {
$percent = convertPercentageDataToDecimal($percentageData);
return $price * $percent;
}
function convertPercentageDataToDecimal($percentageData) {
$start = strpos($percentageData, '(') + 1;
$length = strpos($percentageData, '%') - $start;
$percent = substr($percentageData, $start, $length);
return $percent / 100;
}
var_dump(convertPercentageDataToDecimal($percentageData));
var_dump(multiplyPriceByPercentageData($price, $percentageData));
// output:
// float(0.01)
// float(0.1025)