[warbiscuit]

I'm not positive, but I think it saves the need to create a new execution frame for each lambda call, since the whole loop executes in single frame used by the comprehension.

In theory I suppose the VM could have a map() implementation which opportunistically extracts the code from a lambda and inlines them when possible; but doubt CPython does that. OTOH, I'd be surprised if PyPy doesn't do something like that.

[fovc]

Since Python 3, both generators and lists create a new stack frame. [1] (2nd to last paragraph)

[1] http://python-history.blogspot.com/2010/06/from-list-compreh...

[warbiscuit]

I'm not meaning when the comprehension is invoked, but during each iteration of the loop within the comprehension.

When doing something like `map(lambda x: 2+x, range(100))`, there will be 101 frames created: the outer frame, and 100 for each invocation of the lambda.

Whereas `[2+x for x in range(100)]` will only create 2: one for the outer frame, and one for the comprehension.