php中的四舍五入价格

Question

I want to round up prices in PHP

eg I have the price £74.31 I want to round to the closest 74.35 or if above £74.36 then £74.40 and the decimals I always want to end with 5 and 0 .

For example

£74.31 would be round up to £74.35
£74.32 would be round up to £74.35
£74.33 would be round up to £74.35
£74.34 would be round up to £74.35
£74.35 would be round up to £74.35

£74.36 would be round up to £74.40
£74.37 would be round up to £74.40
£74.38 would be round up to £74.40
£74.39 would be round up to £74.40
£74.40 would be round up to £74.40

I attempted to round up prices with the below

round(($price * $rate) * 2, 1)/2;

Answer 1

You can also try with this logic,

<?php
    $x = 74.31;
    $number = $x*100;
    if($number % 5){
      $number = $number + 5 - ($number % 5);
    }else{
      $number = $number - ($number % 5);
    }
    $number /=100;
    echo number_format((float)$number, 2, '.', '');
?>

Live demo : https://eval.in/748595

Answer 2

Hopefully this makes sense, but if it doesn't some quick background:

The round($number * 2) / 2 you posted works because there are two halves in any whole. If you wanted to round to quarters you would use round($number * 4)/4 , and fifths would be round($number * 5)/5 . etc, etc.

Because it appears as if you want to round to the nearest nickel, there are 20 nickels in a dollar. Problem is that it is willing to move itself up/down. The same thing happens using ceil() , but it will only move upwards, which appears to be what you want.

function round_to_nickel($item, $decimals=false){
    $num = ceil($item * 20) / 20;
    return ($decimals) ? number_format($num, (int)$decimals) : $num;
}

Answer 3

根据您的要求使用 php floor()和ceil()和round()函数。

Answer 4

ceil() , floor() , and round() alone will not produce the correct/desired result; additional calculations are required.

After multiplying the input by 20 then subtracting .1 , then call ceil() , finally divide by 20 . By effect, numbers originally ending in 5 (in the hundredths place) will not be rounded up, but actually remain unchanged.

For clean, concise formatting of the new float value, I recommend printf() with a format parameter that demands two decimal places in the output.

printf('£%.02f', $num, ceil($num * 20 - .1) / 20)

Unit Tests : ( Demo )

for ($num = 74.30; $num < 74.41; $num += .01) {
    var_export(sprintf('%.02f => £%.02f', $num, ceil($num * 20 - .1) / 20));
    echo "\n";
}    

Output:

'74.30 => £74.30'
'74.31 => £74.35'
'74.32 => £74.35'
'74.33 => £74.35'
'74.34 => £74.35'
'74.35 => £74.35'  #not rounded up to 74.40
'74.36 => £74.40'
'74.37 => £74.40'
'74.38 => £74.40'
'74.39 => £74.40'
'74.40 => £74.40'