Dennis Lee Bieber <[email protected]> writes:
>> menu.add_command(label = str(k), command = lambda: f(k))
> I'm not sure, but what effect does
> menu.add_command(label=str(k), command = lambda k=k: f(k))
> have on the processing.
In the first example, k is a free variable in the lambda, so it's
captured from the outer scope when the lambda is evaluated:
>>> k = 3
>>> a = lambda: k
>>> k = 5
>>> a()
5
In the second example, k is bound as an arg to the lambda when the
lambda runs, initialized to the default value supplied when the lambda
was created:
>>> k = 3
>>> a = lambda k=5: k
>>> a()
5
In the weird looking k=k syntax, the "=k" gets k from the outer scope,
and uses it as a default value for the function arg that is bound in the
function. I.e. if k=3 then lambda k=k: ... is like lambda k=3:...
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