Converting STRING to FLOAT?

[daveprout]

Hey all, I am trying to convert a tokenized string to a float type. Specifically, I have queried the normal of a polygon, and I am trying to extract its values to compare them with the values of other normals.

Does anyone know how to convert a string to a float?

Thanks for your help.
Dave Prout
Lead Artist
Spark Unlimited, Inc.

[gmask]

This works for me??

float $x;
string $a="190.00";

$x=$a;

// Result: 190 //

Can you cite an example?

[ze_taupe]

you can use a mel command like that:

float $x;
string $a="190.00";

$x=(float)$a;

it works too....

[empleh]

My handy dandy "Complete Maya Programming" book, by one David A. D. Gould, arrived yesterday. I was thumbing through last night before I went to sleep and, oddly enough, this very subject was one of the first things that I saw in the appendix. "The Man" says that all that you need to convert a string to a number is a valid number in the string. So.

$aString="123";
$aFloat=$aString;
$anInt=$aString;

$aFloat == 123.0;
$anInt == 123;

When you use a (float) or (int) to cast a value those tags are just ingored. The work is done automatically.

Just thought it was neat that one of the first things I saw was an answer to a question I just read.

ww

[daveprout]

Thanks all, I found another method...

string $endor[] = polyInfo -fn;
string $yoda = float($endor[0]);

Dave Prout
Lead Artist
Spark Unlimited, Inc.

[markwilkins]

Yes, Maya does automatic type casting, which is often handy.

Slightly off the topic (but not that far) it drives me nuts that there's no built-in way to ROUND (rather than truncate) a float to an int according to the usual rule. The only way to do this is to write a function.

(Note that this function only correctly handles positive numbers because I'm feeling a little lazy right now.)

proc int round_positive_float (float $mynum)
{
int $int_part = $mynum;
float $frac_part = $mynum - $int_part;

if ($frac_part < 0.5) {
return $int_part;
}
else {
return ($int_part + 1);
}
}

---

Mark R. Wilkins
author of MEL Scripting for Maya Animators
www.melscripting.com

[empleh]

If you wanted a simple method to use inline you could just do this:

For positive numbers.
$anInt=$aFloat+.5;

Or for all values except 0.0
$anInt=$aFloat+(.5*($aFloat/abs($aFloat)));

It isn't as intuitive, but it's easy to implement in line if you only need it once.

Nice looking book Mark. If I ever have money again (and don't have to rely on holidays to acquire my wants) I'd like to have a copy on my desk.

ww

[markwilkins]

Hey, thanks! I keep seeing that trick and forgetting it whenever it would come in handy!! :-/

-- Mark

---

Mark R. Wilkins
author of MEL Scripting for Maya Animators
www.melscripting.com

[jmvfernandes]

Hi,
Did you ever find out how to solve this problem?
I have read the other posts and none of the sollutions helped me.
I am trying to get the values of a face normal so I can do something with it. But the polyInfo -fn returns a string with a lot of garbage: "FACE_NORMAL 4: 1.000000 0.000000 0.000000" and it is not a string array either. Do you know a workaround I can use to get only the normal values of a face (x,y,z)?

Thanks,

Jose

[markwilkins]

If you're getting that back as one string, you can use the tokenize command to split it up into an array. Does that help?

-- Mark

[bentneuron]

This is what I do:

string $normal = polyInfo -fn;
string $tokens[];
tokenize($normal[0], " ", $tokens); // may not need the "[0]" in the "$normal[0]"
$x = $tokens[2];
$y = $tokens[3];
$z = $tokens[4];

-bN

[bentneuron]

oops, sorry I forgot the last part should read:

$x = float($tokens[2]);
$y = float($tokens[3]);
$z = float($tokens[4]);