How to return the value of a recursive function

Question

I have recursive function which walk nested dict and return needed key's value:

def recurs(l):
    for key in l.keys():
        if key == '_events':
            return l[key]
        else:
            recurs(l[key])

c=recurs(d)
print c

And how i can get these values?

Right now its return None, but dict have two lists, and then i try to use yield its return empty iter object — Denis
– Denis, Commented Aug 1, 2011 at 12:41
It does not make sense (logically) to return a (one) value from the function as it calls recurs potentially several times. So the question is, what kind of return value do you expect? A single value? A list? — Felix Kling
– Felix Kling, Commented Aug 1, 2011 at 12:44

Sven Marnach · Accepted Answer · 2011-08-01 12:42:31Z

3

The easiest way to get a flattened iterator is to write a generator function:

def recurs(l):
    for key in l.keys():
        if key == '_events':
            yield l[key]
        else:
            for x in recurs(l[key]):
                yield x

answered Aug 1, 2011 at 12:42

Sven Marnach

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Comments

Roman Bodnarchuk · Accepted Answer · 2011-08-01 12:41:30Z

1

Just return it:

def recurs(l):
    for key in l.keys():
        if key == '_events':
            return l[key]
        else:
            return recurs(l[key])

answered Aug 1, 2011 at 12:41

Roman Bodnarchuk

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4 Comments

Felix Kling Over a year ago

That will terminate the loop after the first iteration. Although I don't understand what the loop is for...

Denis Over a year ago

and instead of two lists of values I get one

Roman Bodnarchuk Over a year ago

@Felix I suppose OP need single value.

Felix Kling Over a year ago

@Roman: But which one? Why do you think he wants the first?

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