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Php – Regex to get decimal zeros

My regex doesn’t work as expected when I run my code, but when I test it on a website the regex does exactly as expected. See my function:

function checkDecimais($numero){

            if($numero > 0){
                preg_match('/^([0]+).([0]*)([1-9])/', $numero, $matches);

                if(isset($matches[2])){
                    return strlen($matches[2]);
                }else{
                    return 0;  
                }

            }else{
                return 0;
            }
}

If I call it like this: checkDecimais(0.0009) it works and returns the number 3, as it has 3 decimal zero digits. However, if I call it like this: checkDecimais(0.00009) , it stops working and returns 0, because my regex is only taking up to 3 zero digits and ignoring when there are more than three digits?

If I change it to string checkDecimais('0.0009') , it works, however I’m giving it numbers and I can’t understand why it doesn’t work.

Can anybody help me ?

I’ve already tried using other regex, but they all have the same problem, it only takes the first 3 zeros when the data is of type number.

Tags:

2

Answers


  1. 0

    Echoing $numero will reveal the problem:

    9.0E-5

    When you use a number, in a function that expects a string, PHP has to convert it. PHP’s default way of doing so seems to use scientific notation for 0.00009, but not for 0.0009. The converted form of 0.00009 is "9.0E-5", which does not match your regular expression because it does not start with a zero.

    Instead, pas a string as your argument to your regular expression:

    echo checkDecimais("0.00009");

    Or, convert a number to a string explicitly using a format of your choice:

    $numero = sprintf("%f", 0.00009);
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  2. 0

    Regular Expression match characters in strings. You do not use strict types so PHP will cast the number into a string automatically. For a 0.00009 this will result in the scientific notation 9.0E-5.

    You can use number_format() to specify how the number is formatted into a string.

    $data = [
    0.009,
    0.0009,
    0.00009,
];

foreach ($data as $numero) {
    echo $numero, ' - ', number_format($numero, 10, '.', ''), ' - ', checkDecimais($numero), "n";
}


function checkDecimais(float $numero): int {

    $subject = number_format($numero, 10, '.', '');
    if ($numero > 0) {
        preg_match('/^([0]+).([0]*)([1-9])/', $subject, $matches);

        if(isset($matches[2])){
            return strlen($matches[2]);
        }else{
            return 0;  
        }

    } else {
        return 0;
    }
}

    Output:

    0.009 - 0.0090000000 - 2
0.0009 - 0.0009000000 - 3
9.0E-5 - 0.0000900000 - 4
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