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 - http://stackoverflow.com/questions/4276516/problem-with-floats-in-php — Zdenek Machek, Mar 27 '13 at 14:59

score 5 · Accepted Answer · answered Mar 27 '13 at 14:59

5

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

answered Mar 27 '13 at 14:59

deceze

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is_numeric? Well.. hem... OK. – Nicolas Le Thierry d'Ennequin Mar 27 '13 at 15:13
Makes sense if you think about it, no? ;-3 – deceze Mar 27 '13 at 15:17
That's the trouble with PHP. Too many built-in functions with imprectidable names (well, not this one)! – Nicolas Le Thierry d'Ennequin Mar 27 '13 at 15:53
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... :) – deceze Mar 27 '13 at 15:58

score 1 · Answer 2 · answered Mar 27 '13 at 15:05

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 '13 at 15:05

Jurijs Nesterovs

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score 0 · Answer 3 · answered Mar 27 '13 at 14:59

0

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

answered Mar 27 '13 at 14:59

Jurijs Kastanovs

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PHP : convert String to Float when possible

3 Answers3