Python iteration with API?

[Anonymous]

Hi,

Using a simple iterator class in python I would like to use a for next loop. I really hate using a while loop, as eventually I will forget to type "stuff.next()" in the while part and maya will implode forever.

This code prints out the items that are currently selected.

import maya.OpenMaya as OM

#Assign all selected objects to a selection list
list = OM.MSelectionList()
OM.MGlobal_getActiveSelectionList(list)
stuff = OM.MItSelectionList(list)

while not stuff.isDone():
      
   dpath= OM.MDagPath()   
   stuff.getDagPath(dpath)
   print dpath.partialPathName()
   stuff.next()

Under the python documentation it seems that I should be able to loop through
iterators like this..

for item in iter(stuff):

This returns the error
# TypeError: 'MItSelectionList' object is not callable #

Is there any general way to use iterator API functions in python without while loops?

[Anonymous]

It's not a python iterator, so the best you can do is
wrap it in one:

def mIter(mit):
    while not mit.isDone():
        yield mit
        mit.next()

list = OM.MSelectionList()
OM.MGlobal_getActiveSelectionList(list)

for item in mIter(OM.MItSelectionList(list)):
    dpath= OM.MDagPath()      
    item.getDagPath(dpath)
    print dpath.partialPathName()

[Anonymous]

Thanks for your response. That reduces potentially lots of "while loops" to one.

My problem formed because I looked in the iterator class for a function that returns the number of elements in the list. Originally I was using MItMeshPolygon and it had a count() function so I had a for loop. But then I found the most used Iterator function MItSelectionList
had no function that returned the number of members.
BUT I found that MSelectionList DOES!!!

import maya.OpenMaya as OM

#Assign all selected objects to a selection list
list = OM.MSelectionList()
OM.MGlobal_getActiveSelectionList(list)
stuff = OM.MItSelectionList(list)

for i in range(0,list.length()):
      
   dpath= OM.MDagPath()   
   stuff.getDagPath(dpath)
   print dpath.partialPathName()
   stuff.next() 

There still is the possibility of putting the .next() on the wrong space. But no infinite loops. It would just repeat the same functions and stop.

YEAH!!!