How to make number like 3.0000000054978E+38 to 3.00 in PHP?
Many thanks!
You cannot use round to solve this since it is a number in scientific notation. You can, however, use substr:
$i = 3.0000000054978E+38;
$i = substr($i, 0, 2); // $i is now the string 3.00
echo( number_format($i+1,2) ); // Will output 4.00
In case you are looking for the small fraction of your number being outputted in a formatted fashion:
$number = 3.0000000054978E+38;
printf('%.2f', $number / 1E+38); # 3.00
You can just use round, as in round($floating_number, 2).
sprintf() always gives you the specified number of decimal points, if you require.
sprintf('%0.2f', 3.0000000);
Would display 3.00, if you echo it.
Related
I am looking for a solution for a smart number formatting in PHP.
For example we have 2 numbers below and we need 4 digits after decimal:
1.12345678
0.00002345678
Using normal number formatting, here are the results:
1.1234 // Looking good
0.0000 // No good
Can we make it keep going until there are 4 non-zero digits? If it can return 0.00002345, perfect!!!
Many thanks!!!
Might be overkill and the pattern could be optimized, but for fun; get optional 0s AND 4 NOT 0s after the .:
preg_match('/\d+\.([0]+)?[^0]{4}/', $num, $match);
echo $match[0];
To round it we can get 5 digits after the 0s and then format it to the length of that -1 (which will round):
preg_match('/\d+\.([0]+?[^0]{5})/', $num, $match);
echo number_format($match[0], strlen($match[1])-1);
For $num = '1234.000023456777'; the result will be 1,234.00002346 and the $matches will contain:
Array
(
[0] => 1234.000023456
[1] => 000023456
)
So this is the code I made to slove this:
$num = 0.00002345678;
$num_as_string = number_format($num,PHP_FLOAT_DIG,'.','');
$zeros = strspn($num_as_string, "0", strpos($num_as_string, ".")+1);
echo number_format($num, (4+$zeros), '.', '');
It converts the float number to a string, checks how many zeros exist after the decimal point and then does a number format with the extra zeros accounted for.
Note that it may break if your float is too big, you can change PHP_FLOAT_DIG to a number larger that may fix that.
Need to round 30.61 to 30.60, Any built-in function for PHP to do this ?
If I understand your desired output correctly, that you only want to round the second decimal point, you can round with 1 decimal presicion, then use numer_format() to ensure you get the correct number of decimals.
$num = 30.61;
echo number_format(round($num, 1), 2);
round() documentation
number_format() documentation
Live demo
you can do this
$num = 3.61;
/*round to nearest decimal place*/
$test_number = round($num,1);
/* ans :3.6
format to 2 decimal place*/
$test_number = sprintf ("%.2f", $test_number);
/* ans : 3.60 */
php function round not working correctly.
I have number 0.9950.
I put code:
$num = round("0.9950", 2);
And I get 1.0? Why?? Why I can't get 0.99?
You can add a third parameter to the function to make it do what you need.
You have to choose from one of the following :
PHP_ROUND_HALF_UP
PHP_ROUND_HALF_DOWN
PHP_ROUND_HALF_EVEN
PHP_ROUND_HALF_ODD
This constants are easy enough to understand, so just use the adapted one :)
In your example, to get 0.99, you'll need to use :
<?php echo round("0.9950", 2, PHP_ROUND_HALF_DOWN); ?>
DEMO
When you round 0.9950 to two decimal places, you get 1.00 because this is how rounding works. If you want an operation which would result in 0.99 then perhaps you are looking for floating point truncation. One option to truncate a floating point number to two decimal places is to multiply by 100, cast to integer, then divide again by 100:
$num = "0.9950";
$output = (int)(100*$num) / 100;
echo $output;
0.99
This trick works because after the first step 0.9950 becomes 99.50, which, when cast to integer becomes just 99, discarding everything after the second decimal place in the original number. Then, we divide again by 100 to restore the original number, minus what we want truncated.
Demo
Just tested in PHP Sandbox... PHP seems funny sometimes.
<?php
$n = 16.90;
echo (100*$n)%100, "\n"; // 89
echo (int)(100*$n)%100, "\n"; // 89
echo 100*($n - (int)($n)), "\n"; // 90
echo (int)(100*($n - (int)($n))), "\n"; // 89
echo round(100*($n - (int)($n))), "\n"; // 90
$quantity = 20;
$product_rate = 66.79;
$total = $quantity * $product_rate;
echo $total;
Output is showing 1335.8000000000002
is there possible to show 1335.8 using php..?
You can use the number_format() function like this:
$firstNum = 1335.8000000000002;
$number = number_format($firstNum, 1, '.', '');
echo $number;
outputs:
1335.8
more on number_format() here: http://php.net/number-format.
You can also multiply the number by 10, then use intval() to convert it to an integer (that way stripping out the decimals) and then divide by 10 like this:
$firstNum = 1335.8000000000002;
$number = 10 * intval($firstNum)/10;
echo $number;
outputs:
1335.8
Note: when using the methods above there will be no rounding, for rounding you would use something like this:
$number = round($firstNum, 1);
echo $number;
which in this case also outputs:
1335.8
Do you really use these variable values? I'm using PHP7 and the output for your given values is 1335.8. If you do a manual calculation it is the same result. It should be 1335.8. Anyway if you need to roundup the value you can use below.
round($total,1);
Please refer the below link and you will be able to grab more details.
http://php.net/manual/en/function.round.php
Because how floating point numbers work, they cannot represent every numbers exactly, so approximations are made.
The closest representation of 20 is 20, it can represent 20 exactly, but 66.79 for instance is approximated to 66.7900000000000062527760746889, that times 20 is 1335.800000000000125055521493778 that again cannot be represented and is approximated to 1335.80000000000018189894035459.
Depending on how you choose to print this number, it may round different ways, in your case for some reason you decided to print 13 decimal places so it rounded to 1335.8000000000002, but if you print only 1 or 2 decimal places it will print as 1335.8 or 1335.80. Just be mindful about that when printing floating point numbers, you may want to specify how many decimal places are relevant to you. For that, use number_format().
Example:
echo number_format($number, 2); // prints 2 decimal places
You can do this simply using echo echo round($total, 1) instead of doing round($total)
How can I separate a number and get the first two digits in PHP?
For example: 1345 -> I want this output=> 13 or 1542 I want 15.
one possibility would be to use substr:
echo substr($mynumber, 0, 2);
EDIT:
please not that, like hakre said, this will break for negative numbers or small numbers with decimal places. his solution is the better one, as he's doing some checks to avoid this.
First of all you need to normalize your number, because not all numbers in PHP consist of digits only. You might be looking for an integer number:
$number = (int) $number;
Problems you can run in here is the range of integer numbers in PHP or rounding issues, see Integers Docs, INF comes to mind as well.
As the number now is an integer, you can use it in string context and extract the first two characters which will be the first two digits if the number is not negative. If the number is negative, the sign needs to be preserved:
$twoDigits = substr($number, 0, $number < 0 ? 3 : 2);
See the Demo.
Shouldn't be too hard? A simple substring should do the trick (you can treat numbers as strings in a loosely typed language like PHP).
See the PHP manual page for the substr() function.
Something like this:
$output = substr($input, 0, 2); //get first two characters (digits)
You can get the string value of your number then get the part you want using
substr.
this should do what you want
$length = 2;
$newstr = substr($string, $lenght);
With strong type-hinting in new version of PHP (> PHP 7.3) you can't use substr on a function if you have integer or float. Yes, you can cast as string but it's not a good solution.
You can divide by some ten factor and recast to int.
$number = 1345;
$mynumber = (int)($number/100);
echo $mynumber;
Display: 13
If you don't want to use substr you can divide your number by 10 until it has 2 digits:
<?php
function foo($i) {
$i = abs((int)$i);
while ($i > 99)
$i = $i / 10;
return $i;
}
will give you first two digits