Speed: Maya API vs. CMDS vs. PyMel

If you have to deal with attributes on a large set of objects, learning a little API or at least avoiding PyMel, might be worth a try. Here are some test results and the code run to acquire them:

Searching 44.000 transforms, to see it they have a specific custom attr (where every fourth node has it..)

With PyMel:
Time Taken: 26.2123000353

 
import maya.OpenMaya as OpenMaya

import maya.cmds as mc
import pymel.core as pm
import time

customAttr = "MyTag"

class Timer():
    def __init__(self):
        self.start = None
    def __enter__(self):
        self.start = time.clock()
    def __exit__(self, type, value, traceback):
        print 'Time Taken: {0}'.format(time.clock() - self.start)

print "\nSearching 44.000 transforms, to see it they have a specific custom attr (where every third node has it..)"

print "\nWith API:"
with Timer():
    dagIt = OpenMaya.MItDag(OpenMaya.MItDag.kDepthFirst, OpenMaya.MFn.kTransform)
    
    nodesWithAttrAPI = list()
    
    while not dagIt.isDone():
    	depNode = OpenMaya.MFnDagNode(dagIt.currentItem())
    	depNodeAttr = depNode.hasAttribute(customAttr)
    	if depNodeAttr:
    	    path = OpenMaya.MDagPath()
    	    depNode.getPath(path)
    	    nodesWithAttrAPI.append(path.fullPathName())
    	dagIt.next()    	    	

print "\nWith CMDS:"
with Timer():
    nodesWithAttrCMDS = list()
    for transform in mc.ls(type="transform"):
        if mc.attributeQuery(customAttr, node=transform, exists=True):
            nodesWithAttrCMDS.append(transform)
            
print "\nWith PyMel:"
with Timer():
    nodesWithAttrPyMel = list()
    for transform in pm.ls(type="transform"):
        if pm.attributeQuery(customAttr, node=transform, exists=True):
            nodesWithAttrPyMel.append(transform)