Question

For the purpose of the example, var 2 is preset from a database as “147.22” type STRING. var 1 is calculated previously in the script and has 147.22 type FLOAT.

Script:

<?

$var1 = (float)$var1;
$var2 = (float)$var2;

var_dump($var1);
var_dump($var2);

if($var1 < $var2) { echo "hello"; }

?>

My expected results would be that the script NOT echo “hello” since the two values are equal in amount and type.

However here is the output I’m getting:

float(197.22)
float(197.22)
hello

If I do not mess with the types and leave the one a float and the other a string, then it still does not work (this is how I got here in the first place).

If i force the values at the time of execution like this:

$var1 = 147.22;
$var2 = 147.22;

var_dump($var1);
var_dump($var2);

if($var1 < $var2) { echo "hello"; }

?>

I get this, (and it works):

float(197.22)
float(197.22)

Notice no “hello”….

Anyone have any clue wth is going on here?

Answer 1

If one of the floats is calculated numerically, and one is created from string assignment, they could be different. Try the following:

$x = 147.22;
$y = 147.2200000000001;
printf("%.40f\n", $x);
printf("%.40f\n", $y);
var_dump($x);
var_dump($y);
var_dump($x < $y);

outputs

147.2199999999999988631316227838397026062012
147.2200000000001125499693443998694419860840
float(147.22)
float(147.22)
bool(true)

Cast them to a string with a specified precision for comparison.