recurses over a mixed data structure of tuples, lists, and dicts, and returns a copy.

deepcopy.py

# this simple example recurses over a mixed data structure of tuples, lists, and dicts, and returns a copy.

num_recursions = 0

def r(current):
    global num_recursions
    num_recursions += 1
    if isinstance(current, list):
        return [r(i) for i in current]
    elif isinstance(current, dict):
        return {r(k) : r(v) for k, v in current.iteritems()}
    elif isinstance(current, tuple):
        return tuple([r(i) for i in current])
    else:
        return current

def main():
    structure = {1:[1,2,3], 2:{(1,99):None, 2:[(1,2,3,None)]}}
    copy = r(structure)
    print structure == copy
    structure[2] = None
    print structure == copy
    print "number of recursions = {}".format(num_recursions)

if __name__ == '__main__':
    main()