[Tutor] printing tree structure

[karma]

Hi all ,

I have a nested list in the structure
[root,[leftSubtree],[RightSubtree]] that I want to print out. I was
thinking that a recursive solution would work here, but so far I can't
quite get it working. This is what I have so far:

Can someone suggest whether this is suited to a recursive solution and
if so, what am I doing wrong.

Thanks

>>> L = ['a', ['b', ['d', [], []], ['e', [], []]], ['c', ['f', [], []], []]]
>>> def printTree(L):
	for i in L:
           if isinstance(i,str):
		   print 'Root: ', i
	   else:
              print '--Subtree: ', i
              printTree(i)


>>> printTree(L)
Root:  a
--Subtree:  ['b', ['d', [], []], ['e', [], []]]
Root:  b
--Subtree:  ['d', [], []]
Root:  d
--Subtree:  []
--Subtree:  []
--Subtree:  ['e', [], []] # this shouldn't be here
Root:  e
--Subtree:  []
--Subtree:  []
--Subtree:  ['c', ['f', [], []], []]
Root:  c
--Subtree:  ['f', [], []]
Root:  f
--Subtree:  []
--Subtree:  []
--Subtree:  []