Question

“tree” structured list:

[(1,1,(1,1,(1,"1"))),(1,1,1),(1,),1,(1,(1,("1")))]  # may be more complex

1. How to traversing it and print each item – I means the 1 and the “1”?

2. How to generate type list with same structure?

   [(‘int’,’int’,(‘int’,’int’,(‘int’,’str’))),(‘int’,’int’,’int’),(‘int’,),’int’,(‘int’,(‘int’,(‘str’)))]

   the ‘int’, ‘str’ here should be output of type(1) and type(“s”) as it can not been displayed on the question

Thanks!

Answer 1

You can create a generator that will traverse the tree for you for (1).

def traverse(o, tree_types=(list, tuple)):
    if isinstance(o, tree_types):
        for value in o:
            for subvalue in traverse(value):
                yield subvalue
    else:
        yield o

data = [(1,1,(1,1,(1,"1"))),(1,1,1),(1,),1,(1,(1,("1",)))]
print list(traverse(data))
# prints [1, 1, 1, 1, 1, '1', 1, 1, 1, 1, 1, 1, 1, '1']

for value in traverse(data):
    print repr(value)
# prints
# 1
# 1
# 1
# 1
# 1
# '1'
# 1
# 1
# 1
# 1
# 1
# 1
# 1
# '1'

---

Here is one possible approach to (2).

def tree_map(f, o, tree_types=(list, tuple)):
    if isinstance(o, tree_types):
        return type(o)(tree_map(f, value, tree_types) for value in o)
    else:
        return f(o)

data = [(1,1,(1,1,(1,"1"))),(1,1,1),(1,),1,(1,(1,("1",)))]
print tree_map(lambda o: type(o).__name__, data)
# prints [('int', 'int', ('int', 'int', ('int', 'str'))), ('int', 'int', 'int'), ('int',), 'int', ('int', ('int', ('str',)))]