Not Incrementing

[Victor Subervi]

On Thu, Dec 31, 2009 at 12:19 PM, MRAB <python at mrabarnett.plus.com> wrote:

> Victor Subervi wrote:
>
>> Hi;
>> This "pseudo-code" snippet was given to me by Dennis on this list (whose
>> last name escapes me):
>>
>> def printTree(allTrees, level=0):
>>  tree = []
>>  for aTree in allTrees:
>>    for name in sorted(aTree.keys()):
>>      tree.append("%s%s" % ("\t" * level, name))
>>      printTree(aTree[name], level + 1)
>>  return tree
>>
>> The code returns all the categories ("name") just fine. It doesn't,
>> however, increment level. I know from my tests that printTree is only called
>> twice (once for each store) and about half a dozen times recursively within
>> one of those stores. Why doesn't this increment? Full code follows.
>>
> [snip]
>
> 'level' is the amount by which the items should be indented. It doesn't
> need to be incremented for each item (if that's what you mean). When
> 'printTree' calls itself to print a subtree, it passes in level + 1 so
> that the items in the subtree will be indented by one more level.
>

Yeah, that's what level is for *now*. But I need to change that to nest
menus.

>
> The function looks slightly wrong to me because it's appending items to
> a list and returning that list, but ignoring the result of printing the
> subtree when it calls itself. Perhaps it should be this:
>
>
> def printTree(allTrees, level=0):
>    tree = []
>    for aTree in allTrees:
>        for name in sorted(aTree.keys()):
>            tree.append("%s%s" % ("\t" * level, name))
>            tree += printTree(aTree[name], level + 1)
>    return tree
>

How do you concatenate a tuple? If we append tree, we can't concatenate it,
can we?
beno
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