[akavi]

What's the advantage of list comprehension over lambdas (assuming the lambda syntax is decently lightweight)?

I feel like I come down hard on the side of lambdas, but I've never really spent enough time in a language with list comprehension, so there's a good chance I'm missing something.

[quietwhisper]

how can you come down hard on the side of one when you've never experienced the other?

I'm from a non-list-comprehension background too, but recently started working a lot in a large python codebase, and have found the dict/list comprehensions to be beautiful. I'm a huge fan. It's a shame lambda syntax is not the best and it's generally crippled, but comprehensions are a great 80/20 compromise for handling most cases very cleanly.

[cwilkes]

I find it a lot easier to read, part of which is that I'm used to the Scala way of sequence dot map function. When I see the python one I can't remember if the function comes first or the array.

[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.

[brianwawok]

I think it's just less to type really, and it's considered the more standard way to do it.