Use os.path.join to concatenate the directory and file name:
for path, subdirs, files in os.walk(root):
for name in files:
print(os.path.join(path, name))
Note the usage of path and not root in the concatenation, since using root would be incorrect.
In Python 3.4, the pathlib module was added for easier path manipulations. So the equivalent to os.path.join would be:
pathlib.PurePath(path, name)
The advantage of pathlib is that you can use a variety of useful methods on paths. If you use the concrete Path variant you can also do actual OS calls through them, like changing into a directory, deleting the path, opening the file it points to and much more.