CODEWITHSUNDEEP
pythonpython-2.7
Kevin
Kevin

Reputation: 1085

Returning a function call?

Is this:

def outer(x):
    def inner():
        print x
    return inner

>>> outer("foo")()

The same as this:

def outer(x):
    def inner():
        print x
    return inner()

>>> outer("foo")

Both work, but is there a more pythonic way to write something like this?

Upvotes: 0

Views: 54

Answers (2)

alfakini
alfakini

Reputation: 4757

They are different. In your example, the first will return a function, that you can use later, and the second will return None type, because you're returning nothing, just printing x.

Upvotes: 0

Charles Duffy
Charles Duffy

Reputation: 295443

Neither is "more pythonic" in absolute terms, because you would use them in different circumstances.

Returning a function to be called later is appropriate if you're generating a callback to be wired up somewhere else, closing over some inputs (with others to be filled in later), or for similar advanced use cases.

Returning a value or immediately performing a side-effecting action is appropriate if your callers will only be interested in that value or action, and you don't have any particular reason to split the operation into stages.

Upvotes: 3

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