Maya mel script - iterate over array problem / save face count in integer variable

Hupie

Hey there,

I'm having a small problem and somehow I can find a solution on the Internet. I'm trying to iterate over an array of objects and display face count  with a for loop (not for in loop).

I tried various syntax's but somehow I am not able to save the face count into a integer variable, what am I doing wrong?

string $pObjs[] = `ls -sl`; //list selection<br>$objCount = size($pObjs); //object count<br><br>for( $i=0; $i<$objCount; $i++ ){<br>   int $facecount = polyEvaluate -f $pObjs[$i];<br>   print ($facecount);<br>}<br>

output:

// Error:    int $facecount = (polyEvaluate -f $pObjs[$i]);
 //
// Error: Line 5.35: Invalid use of Maya object "polyEvaluate". //
// Error:    int $facecount = (polyEvaluate -f $pObjs[$i]);
 //
// Error: Line 5.43: Invalid use of Maya object "f". //

Klaudio2U

polyEvaluate is a command so it goes in those single quotes as you use in: string $pObjs[] = `ls -sl`;

Instead of this:
int $facecount = polyEvaluate -f $pObjs[$i];
it goes like this:
int $facecount = `polyEvaluate -f $pObjs[$i]`;


Since i am not in front of the computer i cant give it a test if that’s the only problem.

Axi5

Oddly enough, despite the documentation saying that polyEvaluate -f returns an int:

// Error: line 5: Cannot convert data of type int[] to type int. // 

Convert the type to an array and you'll be good to go:

int $facecount[] = `polyEvaluate -f $pObjs[$i]`;

EDIT:
Had an odd thought that the command would return an array of ints when you had multiple objects selected. It would have meant that you could skip the setup/loop. Unfortunately when I was expecting 400, 16 I was instead given 416. So it summed them together to give me a single int in an array.

Does anyone have any idea why that's the case?

I'm not a MEL person I usually stick to Python so maybe this is just normal?

throttlekitty

I'm stumped on that too. Was hoping that getting some sleep would help... but....

$facecount is a regular integer, getting a new value each time the loop runs, I don't get why maya thinks that it should be an array.

Bartalon

Perhaps it has something to do with certain other polyEvaluate flags returning array values, so all return values must be an array.  From what I understand of MEL, a variable can't be redefined once it's been set as something like it can in Python.

That's probably why `ls -sl` always returns an array for a single object also... As annoying as that is.

Hupie

Thank you for all the valuable answers! I think you are right about the return type, Bartalon.

I found out that the real problem I was having is that I was using the single quote character (') instead of the accent grave character (`) when trying to type my own polyEvaluate command.