rounding decimal points

[cssExp]

Suppose a have a variable $num, it can be any values, like for example , 0.7849999999999999. What's the best way to round upwards it to maximum of 2 decimals i.e 0.7849999999999999 to 0.79?

i.e if i were looking for 3 decimal then it would have been 0.785.

[Rubble]

Check out: http://php.net/manual/en/function.round.php

[cssExp]

That seems to do the trick, I feel silly I even posted this

[Snowblind]

That seems to do the trick, I feel silly I even posted this

The PHP manual is excellent. If you haven't I'd suggest you bookmark it

[cssExp]

Another doubt. How do I go about limiting to 2 decimals without rounding?

I checked at the php manual, no specific function that I could see. My idea is to somehow use explode and substr in combination, but is there a simpler way?

example
--------
1.1749999999999998 becomes 1.17
1.1767489999999999 becomes 1.17
1.1021999999999999 becomes 1.1

[Snowblind]

This should do it:

<?php
$number = 1234.50789;
$trunc = preg_replace(
    '/^.*?[0]*([\d\,]+)(([\.][\d]{0,2})([\d]*))?.*?$/',
    '$1$3',
    $number
);
echo $trunc;
?>

From php.net/manual/en/function.number-format.php

There are a few ways you can do it though.

[cssExp]

I'll try it out, as for number_format - yes I considered it, but it adds a 0 along the end is the number if something like 1.1021999999999999.

Originally Posted by Snowblind

This should do it:

<?php
$number = 1234.50789;
$trunc = preg_replace(
    '/^.*?[0]*([\d\,]+)(([\.][\d]{0,2})([\d]*))?.*?$/',
    '$1$3',
    $number
);
echo $trunc;
?>

From php.net/manual/en/function.number-format.php

There are a few ways you can do it though.

[cssExp]

Hi, which of the following will be faster and use the least resources?

$number = 1.1749999999999998;
 
$number = preg_replace('/^.*?[0]*([\d\,]+)(([\.][\d]{0,2})([\d]*))?.*?$/','$1$3', $number);
echo "preg_replace result " . $number . "<br>"; // uses 1 function and 1 variable

$number = 1.1749999999999998;
 
list($num, $dec) = explode(".", $number); $number = $num . "." . substr($dec, 0, 2);
echo "explode_substr result " . $number . "<br>"; // uses 2 functions and 3 variables

I want to use the one that works best, of the two however, I have no clue how preg_replace works and I clearly understand the explode and substr combination.

And in both the if $number is 1.1021999999999999 then the result is 1.10, but I don't want the 0 part as it does not have any value - in this respect I'd like it to be 1.1. Now it's more or less same as number_format($number, 2) which also returns 1.10 . Any suggestions?

[nrg_alpha]

Originally Posted by cssExp

And in both the if $number is 1.1021999999999999 then the result is 1.10, but I don't want the 0 part as it does not have any value - in this respect I'd like it to be 1.1. Now it's more or less same as number_format($number, 2) which also returns 1.10 . Any suggestions?

I wouldn't bother with regex or exploding and such.. given what you are asking, perhaps something along the lines of:

Example:

$number = '1.1021999999999999';

$number = (float) sprintf('%.2f', $number);

echo $number; // Output: 1.1 

?

[nrg_alpha]

Sorry.. didn't take rounding into account:

$number = '123.1031999999999999';
echo $number = (float) sprintf('%.2f', round($number, 2)); // Output: 123.1 

[AnthonySterling]

Originally Posted by nrg_alpha

Sorry.. didn't take rounding into account:

$number = '123.1031999999999999';
echo $number = (float) sprintf('%.2f', round($number, 2)); // Output: 123.1 

Finally some sense, although I do suspect it was RegEx which drew you here.

[nrg_alpha]

Originally Posted by AnthonySterling

Finally some sense, although I do suspect it was RegEx which drew you here.

lol.. it get's pretty bad when you know of my love affair with regex
Granted, I just realized that given the rounding, I could have simply did something like:

$number = '123.1031999999999999';
echo $number = round($number, 2); // Output: 123.1 

Which kind of made the previous sample obsolete (it works harder than it needs to). EDIT - Initially, I didn't use rounding, but when I realized rouding was desired, I simply added the rounding function to the rest of the solution, which wasn't even needed anymore. D'Oh!

[crmalibu]

You could also use arithmetic + integer truncation

echo (int)($n * 100) / 100; 

If you might need a different amount of decimal places, you can use this instead of the constant 100

pow(10, $decimal_places);