[SOLVED] Always round down in 20's

[jaymc]

Do you know how I can always round down to the nearest 20, starting from 0,20,40,60 and so on

 

Example

0 rounds to 0

7 rounds to 0

19 rounds to 0

20 rounds to 0

21 rounds to 20

36 rounds to 20

44 rounds to 40

88 rounds to 80

 

And so on..

 

[DeanWhitehouse]

I don't know any pre-made functions to do this, but you could easily write your own.

[.josh]

$num = floor($num/20) * 20;

[Mark Baker]

Surely 20 should round down to 20, not to 0 (or was that just a typo)

[jaymc]

$num = floor($num/20) * 20;

 

Ah yes, thats how I used to do it

 

That works apart from when $num = any of these 20,40,60,80

 

I need it like this

 

Example

20 rounds to 0

40 rounds to 20

60 rounds to 40

80 rounds to 60

 

Any ideas to get around that issue?

[wildteen88]

$nums = array(0, 1, 7, 20, 40, 55);

foreach($nums as $key => $num)
{
    // check that numb is dividable by 20
    if(num >= 20 && ($num%20 == 0))
        $num -= 20;
    else
         $num = floor($num/20) * 20;

    $rounded[] = $num;
}

echo '<pre>' . print_r($rounded, true) . '</pre>';

 

 

[jaymc]

$nums = array(0, 1, 7, 20, 40, 55);

foreach($nums as $key => $num)
{
    // check that numb is dividable by 20
    if(num >= 20 && ($num%20 == 0))
        $num -= 20;
    else
         $num = floor($num/20) * 20;

    $rounded[] = $num;
}

echo '<pre>' . print_r($rounded, true) . '</pre>';

 

That.. didnt work?

 

$nums = array(0, 1, 7, 20, 40, 55, 60, 80, 81); produced this..

 

Array

(

    [0] => 0

    [1] => 0

    [2] => 0

    [3] => 20

    [4] => 40

    [5] => 40

    [6] => 60

    [7] => 80

    [8] => 80

)

 

[.josh]

$num = floor($num/20) * 20;

 

Ah yes, thats how I used to do it

 

That works apart from when $num = any of these 20,40,60,80

 

I need it like this

 

Example

20 rounds to 0

40 rounds to 20

60 rounds to 40

80 rounds to 60

 

Any ideas to get around that issue?

 

Hey it's your project, so you must know what you're doing.  All I'm gonna say is...does 0 get rounded down to -20? So why would 20 get rounded down to 0, 40 to 20, etc...? Not necessarily arguing; just curious.

[.josh]

Wildteen's code forgot $ for $num

 

if($num >= 20 && ($num%20 == 0))

 

[jaymc]

Wildteen's code forgot $ for $num

 

if($num >= 20 && ($num%20 == 0))

 

 

Yeh just spotted, could not work out why it wasnt working!

 

Cheers guys.