When calculating a golf handicap differential you are supposed to truncate the answer to 1 decimal place without rounding. No idea why but...
I know how to do this using TRUNCATE() in mySQL
SELECT TRUNCATE( 2.365, 1 );
// outputs 2.3
but I was wondering if sprintf() could do this? The only way I know to work with decimal places in a float is ...
echo sprintf("%.1f", 2.365);
// outputs 2.4
What language is this in? Assuming it's C or one of its derivatives, and assuming you always want exactly one decimal place, and assuming your values are always non-negative, you can do this:
float val = 12.3456;
val = floor(val*10.0)/10.0;
sprintf("%.1f", val);
Is there a better way? Probably. This is just what comes to mind.
I find it easier to use string operations: let sprintf round to an extra significant digit, trim, then convert back to a float
function truncate_float(float $float, int $significantDigits = 4): float
{
$format = sprintf('%%.%df', $significantDigits + 1);
return (float) substr(sprintf($format, $float), 0, -1);
}
Related
I am trying to do a 2 digit precision in PHP Laravel project but it doesnt work. I have the value 1234666.6666667 that I want to make 1234666.66 but all the results I've seen in here or/and in other search pages.
This is my code:
$value = 1234666.6666667;
return round($value,2);
any other solution?
EDIT:
As I see, you actually want to floor number to 2 decimal points, not to round it, so this answer could help you:
$value = 1234666.6666667;
floor($value * 100) / 100; // returns 1234666.66
If you want 3 decimal points you need to multiple and divide with 1000, for 4 - with 10000 and etc.
You can use number_format, it convert value to string though, so you lose real float value:
$value = 1234666.6666667;
echo number_format($value, 2, '.', ''); // prints 1234666.67
Use this function.
function truncate($i) {
return floor($i*100) / 100.0;
}
Then you can do
$value = truncate(123.5666666); // 123.56
A pragmatic way is to use round($value - 0.05, 2), but even that gets you into hot water with some edge cases. Floating point numbers just don't round well. It's life I'm afraid. The closest double to 1234666.66 is
1234666.65999999991618096828460693359375
That's what $value will be after applying my formula! Really, if you want exact decimal precision, then you need to use a decimal type. Else use integer types and work in multiples of 100.
For the former choice, see http://de2.php.net/manual/en/ref.bc.php
$value = bcadd($value, 0, 2); // 1234666.6666667 -> 1234666.66
Another more exotic way to solve this issue is to use bcadd() with a dummy value for the $right_operand of 0,
This will give you 2 number after decimal.
I want to round a number and I need a proper integer because I want to use it as an array key. The first "solution" that comes to mind is:
$key = (int)round($number)
However, I am unsure if this will always work. As far as I know (int) just truncates any decimals and since round($number) returns a float with theoretically limited precision, is it possible that round($number) returns something like 7.999999... and then $key is 7 instead of 8?
If this problem actually exists (I don't know how to test for it), how can it be solved? Maybe:
$key = (int)(round($number) + 0.0000000000000000001) // number of zeros chosen arbitrarily
Is there a better solution than this?
To round floats properly, you can use:
ceil($number): round up
round($number, 0): round to the nearest integer
floor($number): round down
Those functions return float, but from Niet the Dark Absol comment: "Integers stored within floats are always accurate, up to around 2^51, which is much more than can be stored in an int anyway."
round(), without a precision set always rounds to the nearest whole number. By default, round rounds to zero decimal places.
So:
$int = 8.998988776636;
round($int) //Will always be 9
$int = 8.344473773737377474;
round($int) //will always be 8
So, if your goal is to use this as a key for an array, this should be fine.
You can, of course, use modes and precision to specify exactly how you want round() to behave. See this.
UPDATE
You might actually be more interested in intval:
echo intval(round(4.7)); //returns int 5
echo intval(round(4.3)); // returns int 4
What about simply adding 1/2 before casting to an int?
eg:
$int = (int) ($float + 0.5);
This should give a predictable result.
Integers stored within floats are always accurate, up to around 253, which is much more than can be stored in an int anyway. I am worrying over nothing.
For My Case, I have to make whole number by float or decimal type
number. By these way i solved my problem. Hope It works For You.
$value1 = "46.2";
$value2 = "46.8";
// If we print by round()
echo round( $value1 ); //return float 46.0
echo round( $value2 ); //return float 47.0
// To Get the integer value
echo intval(round( $value1 )); // return int 46
echo intval(round( $value2 )); // return int 47
My solution:
function money_round(float $val, int $precision = 0): float|int
{
$pow = pow(10, $precision);
$result = (float)(intval((string)($val * $pow)) / $pow);
if (str_contains((string)$result, '.')) {
return (float)(intval((string)($val * $pow)) / $pow);
}
else {
return (int)(intval((string)($val * $pow)) / $pow);
}
}
Round to the nearest integer
$key = round($number, 0);
I know of the PHP function floor() but that doesn't work how I want it to in negative numbers.
This is how floor works
floor( 1234.567); // 1234
floor(-1234.567); // -1235
This is what I WANT
truncate( 1234.567); // 1234
truncate(-1234.567); // -1234
Is there a PHP function that will return -1234?
I know I could do this but I'm hoping for a single built-in function
$num = -1234.567;
echo $num >= 0 ? floor($num) : ceil($num);
Yes intval
intval(1234.567);
intval(-1234.567);
Truncate floats with specific precision:
echo bcdiv(2.56789, 1, 1); // 2.5
echo bcdiv(2.56789, 1, 3); // 2.567
echo bcdiv(-2.56789, 1, 1); // -2.5
echo bcdiv(-2.56789, 1, 3); // -2.567
This method solve the problem with round() function.
Also you can use typecasting (no need to use functions),
(int) 1234.567; // 1234
(int) -1234.567; // -1234
http://php.net/manual/en/language.types.type-juggling.php
You can see the difference between intval and (int) typecasting from here.
another hack is using prefix ~~ :
echo ~~1234.567; // 1234
echo ~~-1234.567; // 1234
it's simpler and faster
Tilde ~ is bitwise NOT operator in PHP and Javascript
Double tilde(~) is a quick way to cast variable as integer, where it is called 'two tildes' to indicate a form of double negation.
It removes everything after the decimal point because the bitwise operators implicitly convert their operands to signed 32-bit integers. This works whether the operands are (floating-point) numbers or strings, and the result is a number
reference:
https://en.wikipedia.org/wiki/Double_tilde
What does ~~ ("double tilde") do in Javascript?
you can use intval(number); but if your number bigger than 2147483648 (and your machine/os is x64) all bigs will be truncated to 2147483648. So you can use
if($number < 0 )
$res = round($number);
else
$res = floor($number);
echo $res;
You can shift the decimal to the desired place, intval, and shift back:
function truncate($number, $precision = 0) {
// warning: precision is limited by the size of the int type
$shift = pow(10, $precision);
return intval($number * $shift)/$shift;
}
Note the warning about size of int -- this is because $number is potentially being multiplied by a large number ($shift) which could make the resulting number too large to be stored as an integer type. Possibly converting to floating point might be better.
You could get fancy with a $base parameter, and sending that to intval(...).
Could (should) also get fancy with error/bounds checking.
An alternative approach would be to treat number as a string, find the decimal point and do a substring at the appropriate place after the decimal based on the desired precision. Relatively speaking, that won't be fast.
I want to convert float value (Eg:1.0000124668092E+14) to Integer in php,what is the best method for this in php.output should be "100001246680920"
What do you mean by converting?
casting*: (int) $float or intval($float)
truncating: floor($float) (down) or ceil($float) (up)
rounding: round($float) - has additional modes, see PHP_ROUND_HALF_... constants
*: casting has some chance, that float values cannot be represented in int (too big, or too small), f.ex. in your case.
PHP_INT_MAX: The largest integer supported in this build of PHP. Usually int(2147483647).
But, you could use the BCMath, or the GMP extensions for handling these large numbers. (Both are boundled, you only need to enable these extensions)
I just want to WARN you about:
>>> (int) (290.15 * 100);
=> 29014
>>> (int) round((290.15 * 100), 0);
=> 29015
Use round()
$float_val = 4.5;
echo round($float_val);
You can also set param for precision and rounding mode, for more info
Update (According to your updated question):
$float_val = 1.0000124668092E+14;
printf('%.0f', $float_val / 1E+14); //Output Rounds Of To 1000012466809201
There is always intval() - Not sure if this is what you were looking for...
example: -
$floatValue = 4.5;
echo intval($floatValue); // Returns 4
It won't round off the value to an integer, but will strip out the decimal and trailing digits, and return the integer before the decimal.
Here is some documentation for this: -
http://php.net/manual/en/function.intval.php
Try this
<?php
$float_val = 1.0000124668092E+14;
echo intval($float_val);
?>
Use round, floor or ceil methods to round it to the closest integer, along with intval() which is limited.
http://php.net/manual/en/function.round.php
http://php.net/manual/en/function.ceil.php
http://php.net/manual/en/function.floor.php
See, I want to write a function that takes a float number parameter and rounds the float to the nearest currency value (a float with two decimal places) but if the float parameter has a zero fraction (that is, all zeroes behind the decimal place) then it returns the float as an integer (or i.e. truncates the decimal part since they're all zeroes anyways.).
However, I'm finding that I can't figure out how to determine if if a fraction has a zero fraction. I don't know if there's a PHP function that already does this. I've looked. The best I can think of is to convert the float number into an integer by casting it first and then subtract the integer part from the float and then check if the difference equals to zero or not.
if($value == round($value))
{
//no decimal, go ahead and truncate.
}
This example compares the value to itself, rounded to 0 decimal places. If the value rounded is the same as the value, you've got no decimal fraction. Plain and simple.
A little trick with PHPs type juggling abilities
if ($a == (int) $a) {
// $a has a zero fraction value
}
I think the best way:
if ((string)$value == (int)$value){
...
}
Example:
$value = 2.22 * 100;
var_dump($value == (int)$value); // false - WRONG!
var_dump($value == round($value)); // false - WRONG!
var_dump((string)$value == (int)$value); // true - OK!
function whatyouneed($number) {
$decimals = 2;
printf("%.".($number == (int)($number) ? '0' : $decimals)."F", $number);
}
So basically it's either printf("%.2F") if you want 2 decimals and printf("%.2F") if you want none.
Well, the problem is that floats aren't exact. Read here if you're interested in finding out why. What I would do is decide on a level of accuracy, for example, 3 decimal places, and base exactness on that. To do that, you multiply it by 1000, cast it to an int, and then check if $your_number % 1000==0.
$mynumber = round($mynumber *1000);
if ($mynumber % 1000==0)
{ isInt() }
Just so you know, you don't have to write a function to do that, there's already one that exists:
$roundedFloat = (float)number_format("1234.1264", 2, ".", ""); // 1234.13
If you want to keep the trailing .00, just omit the float cast (although it will return a string):
$roundedFloatStr = number_format("1234.000", 2, ".", ""); // 1234.00