using * as variable value

[NAS18]

Hello,

May I know is it suitable to use * as variable value

http://pastebin.ubuntu.com/24337819/

The purpose function is to delete an selected object that prefix with myobj*  and delete it. 

thank you so much 

regards 

Nurul

[Justin Israel]

From a python standpoint, yes any value is allowed. From a Maya standpoint, as you expected Maya will use * as a wildcard to match objects.

Also, you have a bug in your example. obj is being shadowed by each value in your loop, so the assignment to "object*" has no effect.

Justin

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[NAS18]

http://pastebin.ubuntu.com/24337966/

This is the original snippet,

It does the job but I still doubt with it..

I made a UI interface that generate sphere and cube . I wrote this snippet so it will act only on cube and only will delete the selected cube as I have a list of cube that start with myCube,myCube1 and etc.

I use the bug to ignore the error warning that i received .. like this  ## Error: ValueError: file <maya console> line 14: No object matches name: myCube1Shape # 

not sure whether I did the right thing or misuse the handling exceptions.

Thanks

On Saturday, April 8, 2017 at 3:49:58 AM UTC+1, Justin Israel wrote:

From a python standpoint, yes any value is allowed. From a Maya standpoint, as you expected Maya will use * as a wildcard to match objects.

Also, you have a bug in your example. obj is being shadowed by each value in your loop, so the assignment to "object*" has no effect.

Justin

On Sat, Apr 8, 2017, 2:24 PM NAS18 <nurulm...@gmail.com> wrote:

Hello,

May I know is it suitable to use * as variable value

http://pastebin.ubuntu.com/24337819/

The purpose function is to delete an selected object that prefix with myobj*  and delete it. 

thank you so much 

regards 

Nurul

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[Alok Gandhi]

I use the bug to ignore the error warning that i received .. like this  ## Error: ValueError: file <maya console> line 14: No object matches name: myCube1Shape # 
not sure whether I did the right thing or misuse the handling exceptions.

It is perfectly ok to `pass` exceptions if you know what you are doing. This is a known technique in python, sometimes referred to as EAFP (stands for `It's easier to ask forgiveness than permission`). You can find more information here.

However, it is strongly advised not to use a bare `except`, which causes every exception to pass silently and not just the one you are anticipating. You should only except what you can handle. In your case, just use except ValueError:

def delcube(self, *args):
    sel = cmds.ls("myCube*", sl=True, dag=True, v=True, ud=False)
    myobj = "myCube*"
    for myobj in sel:
        if myobj == myobj:
            try:
                cmds.delete(myobj)
            except ValueError:
                # Shape Node already deleted
                pass

[Alok Gandhi]

Ah and I forgot to mention, you should not use `myobj` for both the pattern matching and object in selection. It makes the code less clear. Better to use some other name. Here's what I suggest:

def delcube(self, *args):
    sel = cmds.ls("myCube*", sl=True, dag=True, v=True, ud=False)

    todelete = "myCube*"
    for myobj in sel:
        if myobj == todelete:

            try:
                cmds.delete(myobj)
            except ValueError:
                # Shape Node already deleted
                pass

also notice that the try, except should be inside the loop otherwise the for loop will run only once.

[Justin Israel]

I still don't understand comparison between the current item from the selection and "myObj*". Can objects actually have a literal * in their name in Maya? When would this check actually pass?

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[Alok Gandhi]

I still don't understand comparison between the current item from the selection and "myObj*". Can objects actually have a literal * in their name in Maya? When would this check actually pass?

You are right. `*` will have no effect in python. There's a bug.

using:

myobj = 'myCube*'

and then:

if myobj == myobj:

    # delete ...

works, becuase `sel('myobj*', ....) already preselects all the object starting with 'myCube' and then myobj == myobj always evaluates to True (as you pointed the myobj = 'myCube*' is overridden by myobj in sel) thus deleting all the cubes only.

My code, with todelete = 'myCube*' will NOT work but myobj = 'myCube*' will work.

I think the best option would be a simpler:

def delcube(self, *args):
    todelete = cmds.ls("myCube*", sl=True, dag=True, v=True, ud=False)
    for obj in todelete:
        try:
           cmds.delete(obj)

[NAS18]

thanks for the answers guys.

I tried to use this snippet but it does not work..It does not give any error but it does not pass the functionality to the button .but if I use myobj==myobj like old one .it works.even though it is working but still not satisfied. i'm curious. 

[Alok Gandhi]

I tried to use this snippet but it does not work..It does not give any error but it does not pass the functionality to the button .but if I use myobj==myobj like old one .it works.even though it is working but still not satisfied. i'm curious. 

Look at my last post above, it exactly explains what you are looking for. 

[Alok Gandhi]

Just to reiterate, use this, it will work and is much simpler:

def delcube(self, *args):
    todelete = cmds.ls("myCube*", sl=True, dag=True, v=True, ud=False)
    for obj in todelete:
        try:
           cmds.delete(obj)

[NAS18]

it does work.. thank you so much  :)

[Justin Israel]

And to explain again why your snippet didn't work and the myObject==myObject always passes, consider this..

1==1

And then

x=1
x==x

Basically comparing a value to itself is always going to pass.

Justin

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