Using double/float in php

Question

Possible Duplicate:
PHP: show a number to 2 decimal places

$b = $del['Antal'];
$y = $info['Pris'];
$z = $y * $b;

$y comes from a mysql database where its type is "double(10,2)" so that one works when I try echo $y; it responds with two decimals.

But now I would like to multiply it with $b.

For example 10.20 * 2 = 20.40

But right now it is like: 10.20 * 2 = 20.4 (only one decimal)

I want two decimals, what to do? I tried some stuff with the (double) function, but didn't really work out. What to do?

Jean-Philippe Bond · Accepted Answer · 2013-01-20T19:49:31.790

3

You can use number_format :

$b = $del['Antal'];
$y = $info['Pris'];
$z = number_format($y * $b ,2);

The number_format function :

string number_format ( float $number [, int $decimals = 0 ] )

And if you don't want the default format :

string number_format ( float $number , int $decimals = 0 , string $dec_point = '.' , string $thousands_sep = ',' )

edited Jan 20 '13 at 19:49

answered Jan 20 '13 at 19:35

Jean-Philippe Bond

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This partially works... But 1 * 1670.10 = 1,670,10 Which is not correct :( – Simon Sondrup Kristensen Jan 20 '13 at 19:38
what does "partially" mean? – artragis Jan 20 '13 at 19:38
The third and fourth parameters are dec_point and thousands_sep so if you want 1670.10 you can do number_format($y * $b ,2, ".", ""). – Jean-Philippe Bond Jan 20 '13 at 19:44
I understand that you don't want a String because you want to do more math but why you care about having 1 or 2 float number if you want to do more math... You should only care about the String that will be print at the end. – Jean-Philippe Bond Jan 20 '13 at 19:54
Ok I changed it to $z = number_format($y * $b ,2, '.', ''); Just as the php manual says, thank you. – Simon Sondrup Kristensen Jan 20 '13 at 19:55

score 2 · Answer 2 · answered Jan 20 '13 at 19:35

2

You can ensure that you store it at two decimal places by using sprintf and storing it as a string:

$z = sprintf('%.2f', $y * $b);

The %.2f ensure that there are always two digits after the decimal point.

answered Jan 20 '13 at 19:35

jordanm

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This one doesn't work for me since I have to do more math with $z later. So I can't store it as a string – Simon Sondrup Kristensen Jan 20 '13 at 19:49
You can cast it back into a float. – jordanm Jan 20 '13 at 20:21

score 2 · Answer 3 · answered Jan 20 '13 at 19:36

2

The data type you describe are fixed point numbers, not floating point numbers (float). PHP does not have such a data type, however it can format floats for you. And it seems like that is what you are looking for, formatting output.

answered Jan 20 '13 at 19:36

Fabian Schmengler

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it has a float type but it is hidden. In the most naural level of php you use scalar type, but at a lower level you do use true types. An evidence is in the functions `is_int`for example which answers `false`when you say `is_int("14")`. You can also use cast operators. so Jean-Philippe Bond has the right answer. – artragis Jan 20 '13 at 19:38
@artragis you are missing my point. I said, PHP has no *fixed point* data type (like decimal(10,2) in MySQL). Of course it has floats and I don't see how that would be hidden. – Fabian Schmengler Jan 20 '13 at 19:40
oh yes you are right misread you. – artragis Jan 20 '13 at 19:40

score 1 · Answer 4 · answered Jan 20 '13 at 19:34

1

Try floatval:

$z = $y * floatval($b);

Alternatively:

$b = (float) $b;

It should automatically convert to a float, however, if you multiply it by 10.20. Read PHP's documentation on type juggling.

If it's merely a styling thing:

$b = number_format($b, 2);

answered Jan 20 '13 at 19:34

hohner

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Casting it as a float does not ensure two decimal places. I am not the downvoter though. – jordanm Jan 20 '13 at 19:37

Using double/float in php

4 Answers4