Compare floats in php

Question

I want to compare two floats in PHP, like in this sample code:

$a = 0.17;
$b = 1 - 0.83; //0.17
if($a == $b ){
 echo \'a and b are same\';
}
else {
 echo \'a         


        

Answer 1

As said before, be very careful when doing floating point comparisons (whether equal-to, greater-than, or less-than) in PHP. However if you're only ever interested in a few significant digits, you can do something like:

$a = round(0.17, 2);
$b = round(1 - 0.83, 2); //0.17
if($a == $b ){
    echo 'a and b are same';
}
else {
    echo 'a and b are not same';
}

The use of rounding to 2 decimal places (or 3, or 4) will cause the expected result.