CODEWITHSUNDEEP
php
user1035079
user1035079

Reputation: 151

Float value comparison bug

$x = array(
    "0",
    "1689.60",
    "0.00",
    "-200",
    "432.00",
    "33.60"
);

$v = 0;

foreach($x as $p) {
    $v += $p;
}

if($v == 1955.2) {
    echo 'equal';
}

with this simple script I assumed that it will output "equal" but it didn't.

If I changed the value of -200 to -100 and changed the expected result value to 2055.2, it works just fine. I already solved my problem by type casting $v to string but I just want to find out why it didn't work if it's a numeric(integer or float) type.

Upvotes: 0

Views: 337

Answers (1)

lmcphers
lmcphers

Reputation: 468

http://php.net/manual/en/language.types.float.php

The problem here is your floating values, even though they appear very equal, are not due to how PHP (and the computer itself) represents floating point integers. There are a few solutions in the comments on the source to testing floats for equality. I highly recommend going through that source; it's brief and informative.

Upvotes: 1

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