Delete digits after two decimal points, without rounding the value
PhpFunctionRoundingPhp Problem Overview
i have value in php variable like that
$var='2.500000550';
echo $var
what i want is to delete all decimal points after 2 digits.
like now value of variable will be
$var='2.50';
echo $var
> keep in mind this value is coming from mysql databse
but when i use round php function
i got round but i dont need round, i just need to delete all digits after 2 decimal simple.
i have tired, flot()
and lot of other option no success.
Thanks
Php Solutions
Solution 1 - Php
TL;DR:
The PHP native function bcdiv seems to do precisely what is required, and properly.
To simply "truncate" a number, bcdiv($var, 1, 2);
where 2 is the number of decimals to preserve (and 1 is the denomenator - dividing the number by 1 allows you to simply truncate the original number to the desired decimal places)
Full Answer (for history)
This turns out to be more elusive than one might think.
After this answer was (incorrectly) upvoted quite a bit, it has come to my attention that even sprintf will round.
Rather than delete this answer, I'm turning it into a more robust explanation / discussion of each proposed solution.
number_format - Incorrect. (rounds)
Try using number format:
$var = number_format($var, 2, '.', ''); // Last two parameters are optional
echo $var;
// Outputs 2.50
If you want it to be a number, then simply type-cast to a float:
$var = (float)number_format($var, 2, '.', '');
Note: as has been pointed out in the comments, this does in fact round the number.
sprintf - incorrect. (sprintf also rounds)
If not rounding the number is important, then per the answer below, use sprintf:
$var = sprintf("%01.2f", $var);
floor - not quite! (floor rounds negative numbers)
floor, with some math, will come close to doing what you want:
floor(2.56789 * 100) / 100; // 2.56
Where 100 represents the precision you want. If you wanted it to three digits, then:
floor(2.56789 * 1000) / 1000; // 2.567
However, this has a problem with negative numbers. Negative numbers still get rounded, rather than truncated:
floor(-2.56789 * 100) / 100; // -2.57
"Old" Correct answer: function utilizing floor
So a fully robust solution requires a function:
function truncate_number( $number, $precision = 2) {
// Zero causes issues, and no need to truncate
if ( 0 == (int)$number ) {
return $number;
}
// Are we negative?
$negative = $number / abs($number);
// Cast the number to a positive to solve rounding
$number = abs($number);
// Calculate precision number for dividing / multiplying
$precision = pow(10, $precision);
// Run the math, re-applying the negative value to ensure returns correctly negative / positive
return floor( $number * $precision ) / $precision * $negative;
}
Results from the above function:
echo truncate_number(2.56789, 1); // 2.5
echo truncate_number(2.56789); // 2.56
echo truncate_number(2.56789, 3); // 2.567
echo truncate_number(-2.56789, 1); // -2.5
echo truncate_number(-2.56789); // -2.56
echo truncate_number(-2.56789, 3); // -2.567
New Correct Answer
Use the PHP native function bcdiv
echo bcdiv(2.56789, 1, 1); // 2.5
echo bcdiv(2.56789, 1, 2); // 2.56
echo bcdiv(2.56789, 1, 3); // 2.567
echo bcdiv(-2.56789, 1, 1); // -2.5
echo bcdiv(-2.56789, 1, 2); // -2.56
echo bcdiv(-2.56789, 1, 3); // -2.567
Solution 2 - Php
floor(2.500000550 * 100) / 100;
This should do your task...
Solution 3 - Php
You're requesting a function that returns "2.50"
and not 2.5
, so you aren't talking about arithmetic here but string manipulation. Then preg_replace
is your friend:
$truncatedVar = preg_replace('/\.(\d{2}).*/', '.$1', $var);
// "2.500000050" -> "2.50", "2.509" -> "2.50", "-2.509" -> "2.50", "2.5" -> "2.5"
If you want to do it with arithmetic, simply use:
$truncatedVar = round($var * 100) / 100);
// "2.500000050" -> "2.5", "2.599" -> "2.59", "-2.599" -> "2.59"
Solution 4 - Php
try with number_format:
echo number_format('2.50000050', 2); // 2.50
Solution 5 - Php
number_format rounds the number
php > echo number_format(128.20512820513, 2)."\n";
128.21
I used preg_replace to really cut the string
php > echo preg_replace('/(\.\d\d).*/', '$1', 128.20512820513)."\n";
128.20
Solution 6 - Php
someone posted here about
> floor(2.500000550 * 100) / 100;
function cutAfterDot($number, $afterDot = 2){
$a = $number * pow(10, $afterDot);
$b = floor($a);
$c = pow(10, $afterDot);
echo "a $a, b $b, c $c<br/>";
return $b/$c ;
}
echo cutAfterDot(2.05,2);
a 205, b 204, c 100
2.04
so in raw form don't use it... But if you add a little epsilon...
function cutAfterDot($number, $afterDot = 2){
return floor($number * pow(10, $afterDot) + 0.00001) / pow(10, $afterDot);
}
it works!
Solution 7 - Php
Use the PHP native function bcdiv.
Example:
echo bcdiv(3.22871, 1, 1); // 3.2
echo bcdiv(3.22871, 1, 2); // 3.22
echo bcdiv(3.22871, 1, 3); // 3.228
echo bcdiv(-3.22871, 1, 1); // -3.2
echo bcdiv(-3.22871, 1, 2); // -3.22
For your case:
$var='2.500000550';
echo $var
echo bcdiv($var, 1, 2); // 2.50
Solution 8 - Php
use http://php.net/manual/en/function.sprintf.php">sprintf</a>
sprintf("%01.2f", $var);
Solution 9 - Php
The following is (what I believe is - please correct me if not) a robust mathematical* solution, based mostly on the information from several other answerers here, and a small amount from me
(*Which is not to suggest there's anything wrong with Liphtier's regex-based answer - just that I can see purists wanting to avoid regex for what is arguably a mathematical problem.)
sprintf()
,number_format()
(andround()
, obviously), are all performing a rounding operation so are not appropriate for the non-rounding truncation requested in the question (not on their own, at least).- In lieu of an out-of-the-box function, the seemingly most elegant solution was Sujit Agarwal's answer
- But because of the way floats are stored, we need to use an epsilon - as pointed out in David Constantine's answer (where he also makes the previous solution more general by using
pow()
to get the right factor based on a specified precision). - But then, as pointed out in cale_b's answer, any use of
floor()
(or presumablyceil()
) may produce unintended results for negatives without use ofabs()
. - And the value I'm trying to add is:
- If using a division on
abs()
to get a negation factor, we need to account for the special case when the input is 0. - We should dynamically create the epsilon; A static hard-coded epsilon might be too small or too large, depending on the precision required. I haven't seen this issue addressed in the other answers.
The code I'm using is:
public static function truncate_decimal($number, $leavePlaces = 2)
{
if ($number == 0) return 0;
$negate = $number / abs($number);
$shiftFactor = pow(10, $leavePlaces);
$epsilon = pow(10, -1 * $leavePlaces);
return floor(abs($number) * $shiftFactor + $epsilon) / $shiftFactor * $negate;
}
Solution 10 - Php
Already a lot of possible solutions, I just want to add the one that I came up to solve my problem.
function truncate_decimals($number, $decimals=2)
{
$factor = pow(10,$decimals);
$val = intval($number*$factor)/$factor;
return $val;
}
truncate_decimals(199.9349,2);
// 199.93
Solution 11 - Php
All of the solutions which use number_format are wrong because number_format performs rounding.
The function below should work on all numbers, you can specify the decimal separator for those countries which use ','.
function truncate_decimal($number, $truncate_decimal_length = 2, $decimal_character = '.', $thousands_character = '') {
$number = explode($decimal_character, $number);
$number[1] = substr($number[1], 0, $truncate_decimal_length);
$number_truncated = implode($decimal_character, $number);
return number_format($number_truncated, $truncate_decimal_length, $decimal_character, $thousands_character);
}
Solution 12 - Php
A simple function to follow would be "If greater than 0 floor, else ceil", using a multiplier to raise it above the decimal point temporarily whilst doing it:
function trim_num($num_in, $dec_places = 2) {
$multiplier = pow(10, $dec_places); // 10, 100, 1000, etc
if ($num_in > 0) {
$num_out = floor($num_in * $multiplier) / $multiplier;
} else {
$num_out = ceil($num_in * $multiplier) / $multiplier;
}
return $num_out;
}
Solution 13 - Php
$num = 118.74999669307;
$cut = substr($num, 0, ((strpos($num, '.')+1)+2));
// Cut the string from first character to a length of 2 past the decimal.
// substr(cut what, start, ( (find position of decimal)+decimal itself)+spaces after decimal) )
echo $cut;
Solution 14 - Php
> floor - not quite! (floor rounds negative numbers)
A possible solution from cale_b answer.
static public function rateFloor($rate, $decimals)
{
$div = "1" . str_repeat("0", $decimals);
if ($rate > 0) {
return floor($rate * $div) / $div;
}
$return = floor(abs($rate) * $div) / $div;
return -($return);
}
static public function rateCeil($rate, $decimals)
{
$div = "1" . str_repeat("0", $decimals);
if ($rate > 0) {
return ceil($rate * $div) / $div;
}
$return = ceil(abs($rate) * $div) / $div;
return -($return);
}
Positive
> Rate: 0.00302471 > > Floor: 0.00302400 > > Ceil: 0.00302500
Negative
> Rate: -0.00302471 > > Floor: -0.00302400 > > Ceil: -0.00302500
Solution 15 - Php
If you don't want to round the number but you want to remove the decimal places you can use "substr" method
substr(string, start, length);
substr(4.96, 0, -1);