PHP eval give wrong result

Question

Something is wrong with eval function

$string = '$val = 1526.65 - 1519.99;';
eval($string);
echo $val; => give 6.6600000000001, expected 6.66

The test is here : http://sandbox.onlinephpfunctions.com/code/fa5b2e7e6602e60cdeb054b705a69e4a226bd52c

Anyone have an explanation ?

score 5 · Answer 1 · edited May 23 '17 at 12:21

5

This has nothing to do with eval, since the same result is produced by running that line normally. The reason for the strange result is floating point error.

edited May 23 '17 at 12:21

Community

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answered Jul 29 '15 at 15:07

nkorth

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Wouldn't it be better to flag the question as a duplicate if the other question provides answers to this one? – Anonymous Jul 29 '15 at 15:11
Do you have suggestion to bypass this error? Because I need to do correct calculation here... – Thanh Trung Jul 29 '15 at 15:11
@Anonymous Yeah, sorry – nkorth Jul 29 '15 at 15:12
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@ThanhTrung See http://stackoverflow.com/questions/3957705/the-accuracy-of-php-float-calculate for a couple PHP-specific suggestions. – nkorth Jul 29 '15 at 15:13

PHP eval give wrong result

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