PHP : convert String to Float when possible

Question

In PHP, I need to write a function that takes a string and returns its conversion to a float whenever possible, otherwise just returns the input string.

I thought this function would work. Obviously the comparison is wrong, but I don't understand why.

function toNumber ($input) {
    $num = floatval($input); // Returns O for a string
    if ($num == $input) { // Not the right comparison?
        return $num;
    } else {
        return $input;
    }
}

echo(gettype(toNumber("1"))); // double
echo(gettype(toNumber("3.14159"))); // double
echo(gettype(toNumber("Coco"))); // double (expected: string)

Check this - stackoverflow.com/questions/4276516/problem-with-floats-in-php — Zdenek Machek
– Zdenek Machek, Commented Mar 27, 2013 at 14:59

deceze · Accepted Answer · 2013-03-27 14:59:51Z

5

function toNumber($input) {
    return is_numeric($input) ? (float)$input : $input;
}

answered Mar 27, 2013 at 14:59

deceze♦

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4 Comments

Nicolas Le Thierry d'Ennequin Over a year ago

is_numeric? Well.. hem... OK.

deceze Over a year ago

Makes sense if you think about it, no? ;-3

Nicolas Le Thierry d'Ennequin Over a year ago

That's the trouble with PHP. Too many built-in functions with imprectidable names (well, not this one)!

deceze Over a year ago

Mmm, fair enough. It's worth perusing the list of basic functions once or twice though, like all string functions and all number functions. There's aren't that many... :)

Jurijs Nesterovs · Accepted Answer · 2013-03-27 15:05:14Z

1

try if($num){return $num;}else{return $input}, this will work fine, it will only jump to else statement part, when $num = 0

answered Mar 27, 2013 at 15:05

Jurijs Nesterovs

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Comments

Jurijs Kastanovs · Accepted Answer · 2013-03-27 14:59:58Z

0

Well the fastest thing would be checking if $num == 0 rather than $num == $input, if I understand this correctly.

answered Mar 27, 2013 at 14:59

Jurijs Kastanovs

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