Weird result when converting string to float

Question

I want to convert a string to float but I've some problem. Here is my code

    $dataValue = $item[$data];
    $dataValue = trim($dataValue);
    var_dump($dataValue);echo "<br>";
    $dataValue = str_replace(',', '.', $dataValue);
    var_dump($dataValue);echo "<br>";
    var_dump(floatval($dataValue));echo "<br>";
    var_dump(floatval('4.02'));echo "<br>";

And the results

string(7) "4,02"
string(7) "4.02"
float(4)
float(4.02)

I don't understand the third result, why I have 4 and not 4.02 ?

Thanks

EDIT:

My new code :

$dataValue = $item[$data];

        echo mb_detect_encoding($dataValue) . "<br>";

        $dataValue = iconv('ASCII', 'UTF-8//TRANSLIT', $dataValue);
        $dataValue = trim($dataValue);
        $dataValue = str_replace(',', '.', $dataValue);

        echo mb_detect_encoding($dataValue) . "<br>";

        var_dump($dataValue);echo"<br >";
        $dataValue = mb_convert_encoding($dataValue, "UTF-8");
        var_dump($dataValue);echo"<br >";
        $dataValue = str_replace(',', '.', $dataValue);
        $dataValue = floatval($dataValue);
        var_dump($dataValue);echo"<br >";`

And the result

ASCII
ASCII
string(7) "4.02"
string(7) "4.02"
float(4)

Ignacio Vazquez-Abrams · Accepted Answer · 2013-01-16T18:39:49.983

5

There are only 4 visible characters, yet var_dump() claims that there are 7. I surmise that there is an invisible character before the decimal point that is causing floatval() to terminate conversion prematurely. You can verify this by looking at a hex dump of the contents of $dataValue.

EDIT:

It appears that your string is encoded in UTF-16LE. Use mb or iconv to convert it to ASCII/UTF-8 before processing.

edited Jan 16 '13 at 18:39

answered Jan 16 '13 at 18:30

Ignacio Vazquez-Abrams

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yes I think it's the problem. `echo bin2hex($dataValue);` give me `34002c00300032` – guillaume Jan 16 '13 at 18:33
1

`unpack()` will let you get at it. – Ignacio Vazquez-Abrams Jan 16 '13 at 18:34
And `print_r(unpack('H*', $dataValue));` give me `Array ( [1] => 34002c00300032 ) ` – guillaume Jan 16 '13 at 18:37
First, stop trimming it. Then, convert it **from UTF-16LE**. – Ignacio Vazquez-Abrams Jan 16 '13 at 19:35
Now i have `string(5) "4.02"` and after floatval() I have `float(0)` – guillaume Jan 16 '13 at 19:45
I put a trim() after converting, and now it's ok. Thanks for your time ;) – guillaume Jan 16 '13 at 19:46

Bogdan Burym · Answer 2 · 2013-01-16T18:39:53.470

0

Tested this:

$dataValue = "4,02";
$dataValue = trim($dataValue);
var_dump($dataValue);echo "<br>";
$dataValue = str_replace(',', '.', $dataValue);
var_dump($dataValue);echo "<br>";
var_dump(floatval($dataValue));echo "<br>";
var_dump(floatval('4.02'));echo "<br>";

Output:

string(4) "4,02"
string(4) "4.02"
float(4.02)
float(4.02)

Are you sure that the posted code produces the described problem?

EDIT

Try add this this:

$dataValue = preg_replace("/[^0-9\,]/", '', $dataValue);

edited Jan 16 '13 at 18:39

answered Jan 16 '13 at 18:25

Bogdan Burym

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This helps test my theory - in this case, the previously double-quoted string is now in single-quotes. – Southpaw Hare Jan 16 '13 at 18:27
@SouthpawHare Perhaps! Really possible. – Bogdan Burym Jan 16 '13 at 18:28
With your code it's work. But my value provide from an array `$item[$data]` what's weird to is the size of 7 char whereas there is only 4 char visible. – guillaume Jan 16 '13 at 18:29

score 0 · Answer 3 · answered Jan 16 '13 at 18:26

0

Use number_format(float_number, decimal_places):

var_dump(number_format(floatval($dataValue) ,2));

answered Jan 16 '13 at 18:26

mallix

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How is this related to the question? – Ignacio Vazquez-Abrams Jan 16 '13 at 18:27

score 0 · Answer 4 · edited May 23 '17 at 10:24

0

I believe the difference lies in the fast that $dataValue is a double-quoted string in the third output, while you use a single-quoted string in the fourth example. In PHP, these work differently when dealing with how they are treated as literals.

edited May 23 '17 at 10:24

Community

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answered Jan 16 '13 at 18:26

Southpaw Hare

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score 0 · Answer 5 · answered Jan 16 '13 at 18:26

0

I am going to assume it has to do with accuracy issues in PHP's float implementation.

Check out this: Wikipedia: Floating Point Accuracy Problems

answered Jan 16 '13 at 18:26

Erik

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Weird result when converting string to float

5 Answers5