Sorry for late .
Yeah , if everything is string then no problem , if there is no possibility
then will use string instead .
Big thanks , hope you are doing well.
在 2019年5月3日星期五 UTC+8下午12:43:08，Justin Israel写道：
>
>
>
> On Fri, May 3, 2019 at 4:38 PM Zhen Huang <qeej...@gmail.com <javascript:>>
> wrote:
>
>> Hi Justin ,
>>
>> cPickle can deserialize pymel node , and like eval it can't convert back
>> if the node not exists .
>>
>> Thank you ,
>>
>
> Likely because the pymel node constructor wants to validate and fail if it
> doesn't exist, as opposed to letting you have a representation of a node
> that may or may not exist. This is why I was suggesting just storing full
> string paths and then converting each one back into a pymel node and being
> able to handle some that do not exist. If you use strings then you can use
> json.
>
>
>>
>> 在 2019年5月3日星期五 UTC+8上午3:40:51，Justin Israel写道：
>>>
>>>
>>>
>>> On Fri, May 3, 2019, 1:06 AM zhen huang <qee...@gmail.com> wrote:
>>>
>>>> Hi Justin ,
>>>>
>>>> Thank you ! I've tried the json even can't dumps the pymel node data .
>>>> This is why I looked for the eval solution .
>>>> Please check the error out :
>>>> Error: TypeError: file C:\Program
>>>> Files\Autodesk\Maya2017\bin\python27.zip\json\encoder.py line 184:
>>>> nt.Transform(u'pSphere2') is not JSON serializable
>>>>
>>>> Thanks and Regards ,
>>>>
>>>
>>> Convert the PyMel node into a fullpath string and store that. When you
>>> deserialize it back to a dict, you can convert the full path back into a
>>> PyMel node.
>>>
>>> Alternatively you may try using the cPickle module as it may be able
>>> serialize PyMel nodes. Probably better that you just use the full path
>>> though.
>>>
>>>
>>>> 在 2019年5月2日星期四 UTC+8下午6:47:45，Justin Israel写道：
>>>>>
>>>>>
>>>>>
>>>>> On Thu, May 2, 2019, 9:24 PM Zhen Huang <qeej...@gmail.com> wrote:
>>>>>
>>>>>> Hi ,
>>>>>>
>>>>>> I have a question about python build-in function 'eval ' , please
>>>>>> check out the example code below :
>>>>>>
>>>>>> ## create a polySphere , default name : 'pSphere1'
>>>>>>
>>>>>> import pymel.core as pm
>>>>>> from pymel.core import nt
>>>>>>
>>>>>> # initialize a pymel transform node
>>>>>> pymelShpere = pm.PyNode('pSphere1')
>>>>>> # put it to a dict
>>>>>> testDict = {0:pymelShpere}
>>>>>> # convert it to str which can be stored as string in file basic data
>>>>>> strMark = str(testDict)
>>>>>>
>>>>>> # now read it back , if scene has the pShere1 , it will work
>>>>>> perfectly
>>>>>> newDict = eval(strMark)
>>>>>>
>>>>>> # now delete the pShpere1 , and try to convert data to dict , failed
>>>>>> because the pymel nt will try to initialize the string 'pShere1' to
>>>>>> pymel
>>>>>> node
>>>>>> newDict =eval(strMark)
>>>>>>
>>>>>>
>>>>>> My question : if I have lots of nodes store in a string data which
>>>>>> convert from dict , is there a way to just make it out , just ignore
>>>>>> error
>>>>>> part or if node not exists it just convert from nt to string name ?
>>>>>> if pSphere2 not exist then return
>>>>>>
>>>>>> {0:nt.Transform('pSphere1'), 1:'pSphere2' }
>>>>>>
>>>>>>
>>>>>>
>>>>>> Any idea is very much welcome , big thanks !!!
>>>>>>
>>>>>
>>>>> I would advise staying away from the eval() approach. Not only is it
>>>>> going to be inflexible for your current goal, it also can cause unwanted
>>>>> execution of arbitrary logic. A random code snippet that deletes files
>>>>> could be set on a node and your code would blindly execute it as your own
>>>>> user. You don't want random code being evaluated like that.
>>>>>
>>>>> A better approach would be to use a proper serialisation format like
>>>>> json or pickle (protocol version 1 for ascii format). This would allow
>>>>> you
>>>>> to read the data back into a dictionary and then evaluate each value and
>>>>> filter what does and does not exist in the scene.
>>>>>
>>>>>
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