[Tutor] recursive problem

[Roelof Wobben]

Hello, 

 

I have this :

 

def recursive_count(target, nested_num_list):
    """
      >>> recursive_count(2, [2, 9, [2, 1, 13, 2], 8, [2, 6]])
      4
      >>> recursive_count(7, [[9, [7, 1, 13, 2], 8], [7, 6]])
      2
      >>> recursive_count(15, [[9, [7, 1, 13, 2], 8], [2, 6]])
      0
      >>> recursive_count(5, [[5, [5, [1, 5], 5], 5], [5, 6]])
      6
    """
    for element in nested_num_list:
        if type(element) == type([]):
           test = recursive_count(target, element)
        print element, target
        if element == target :
           count = count + 1
    return count

 

if __name__ == "__main__":
    import doctest
    doctest.testmod()

 

 

Now I get this message :

 

UnboundLocalError: local variable 'count' referenced before assignment

 

But if I do this :

 

def recursive_count(target, nested_num_list):
    """
      >>> recursive_count(2, [2, 9, [2, 1, 13, 2], 8, [2, 6]])
      4
      >>> recursive_count(7, [[9, [7, 1, 13, 2], 8], [7, 6]])
      2
      >>> recursive_count(15, [[9, [7, 1, 13, 2], 8], [2, 6]])
      0
      >>> recursive_count(5, [[5, [5, [1, 5], 5], 5], [5, 6]])
      6
    """
  count = 0 

  for element in nested_num_list:
        if type(element) == type([]):
           test = recursive_count(target, element)
        print element, target
        if element == target :
           count = count + 1
    return count

 

if __name__ == "__main__":
    import doctest
    doctest.testmod()

 

The count will always be 0 if a nested list is being found.

 

What's the python way to solve this 

 

Roelof

 
 		 	   		  
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