Maya python get top most parent transforms

Question

I have a selection of transforms in maya and I want to get the top parent transforms of all hierarchies within the selection. Is this the best way to achieve that?

import maya.cmds as cmds
def getTopParents(transforms):
    '''
    Returns a list of the top most parents for the given transforms
    '''
    parents = []
    for t in transforms:
        p = cmds.listRelatives(t, parent=True, type='transform')
        while p:
            p = cmds.listRelatives(p[0], parent=True, type='transform')
        if p:
            parents.append(p[0])
        else:
            parents.append(t)

    return parents

Answer 1

How about something like this? Modify as needed to store the parents instead of just printing them.

import maya.cmds as cmds

targets = ['pCylinder1', 'group4', 'group10']

print('Full hierarchy: {}'.format(cmds.ls(targets[0], long=True)[0]))

for target in targets:
    parent = None
    stop = False
    
    while not stop:
        p = cmds.listRelatives(parent or target, parent=True)
        if p is None:
            stop = True
        else:
            parent = p[0]
            
           
    if parent:
        print('{} has top-level parent {}'.format(target, parent))
    else:
        print('{} is top-level object'.format(target))

Output:

Full hierarchy: |group10|group9|group8|group7|group6|group5|group4|group3|group2|group1|pCylinder1
pCylinder1 has top-level parent group10
group4 has top-level parent group10
group10 is top-level object

Edit: Looks like I didn't read your question properly. We more or less came up with the same code, so I suppose my answer to your question is Yes, this is probably the best way.

You can also use the full path of an object and split by |, but it's not necessarily as precise as it sounds -- especially if the objects gets passed to your method by their short names.