im searching for a good example easy to understand on what the join command really does.
it seems its similar to other combined functions like zip or combineLatest perhaps but it mentions having a window of time that it can join... can anyone give a real world example of how to use it ?
i tried so far something like this:
Observable.just(1,2,3).join(Observable.just(4,5,6,7))
but this does not compile.its asking for a leftEnd and a rightEnd functions. but i'm confused what i need to do here and the documentation is a bit confusing.
Related
I'm trying to figure out when to use ViewportAdapter, BoxingViewportAdapter, WindowViewportAdapter, ScalingViewportAdapter and DefaultViewportAdapter in Monogame.Extended. I've played around with them a bit, and I think i have a pretty good understanding of what ScalingViewportAdapter does, but not the rest.
How should I use them? The docs at https://www.monogameextended.net/ does not have a detailed explanation of the classes.
This is really bad if it is what I think it is. I'm still learning Scala so I could be missing something HUGE but if I need constant time access to a specific element in a JObject, wouldn't storing the elements as a List(Tuple2) be REALLY REALLY REALLY bad for runtime?
I'm working on an application which uses Spark... and it looks like Spark is using json4s. I could imagine there's a good reasoning behind this, or maybe I don't know enough about Scala yet to understand why this doesn't matter.
Any thoughts?
So, I'm currently trying to make an extensible wrapper for pymongo and I found myself wishing that it was possible to query a cursor. This is mostly for making the api as clean as possible. Basically what I was imagining was something along these lines:
def get_all_x_type(collection):
return collection.find({"type":"x"})
def get_all_y_kind(collection):
return collection.find({"kind": "y"})
def get_all_x_and_y(collection):
return get_all_x(get_all_y(collection))
Implementation details are actually nicer than that, but that's the general functionality I'm looking for. I know it's possible to just extend the find query, but I would like to be able to deal with cursors passed to me from other people. Is there any way to do something like this? I could checks on the cursor as I iterate through it, but that seems pretty gross and I was looking for something a bit cleaner.
Alternately is this a silly idea for some reason? I'm not a mongo expert by any means, but this functionality seemed useful to me, but it might just be my naivete.
I've run into a frustrating feature of KVO: all notifications are funneled through a single method (observeValueForKeyPath:....), requiring a bunch of IF statements if the object is observing numerous properties.
The ideal solution would be to pass a method as an argument to the method that establishes the observing in the first place, but it seems this isn't possible. Does a solution exist to this problem? I initially considered using the keyPath argument (addObserver:forKeyPath:options:context:) to call a method via NSSelectorFromString, but then I came across the post KVO Dispatcher pattern with Method as context and the article it linked to which offers a different solution in order to pass arguments along as well (although I haven't gotten that working yet).
I know a lot of people have come up against this issue. Has a standard way of handling it emerged?
OP asks:
Has a standard way of handling it emerged?
No, not really. There are a lot of different approaches out there. Here are some:
https://github.com/sleroux/KVO-Blocks
http://pandamonia.github.io/BlocksKit
http://www.mikeash.com/pyblog/friday-qa-2012-03-02-key-value-observing-done-right-take-2.html
https://github.com/ReactiveCocoa/ReactiveCocoa
http://blog.andymatuschak.org/post/156229939/kvo-blocks-block-callbacks-for-cocoa-observers
Seriously, there are a ton of these... Google "KVO blocks"
I can't say that any of the options I've seen seem prevalent enough to earn the title "standard way". I suspect most folks who feel motivated to conquer this issue just pick one and go with it, or write their own -- it's not as if adapting KVO to use block based callbacks is rocket science. The Method-based approach you link to doesn't seem like a step forward for simplicity. I get that you're trying to take the uncertainty of the string-based-key-path <-> method conversion out of the equation, but that kind of falls down because not all observable keys/keyPaths are methods. (If nothing else, you can observe arbitrary keys on NSMutableDictionaries and get notifications.)
It sure would be nice if Apple would release a new blocks-based KVO API, but I'm not holding my breath. But in the meantime, like I said, just pick one you like and use it or write your own and use that.
What's the best way to go about autogenerated keys for Pilog? i've
been digging around a bit and can't find anything related.
Hints and pointers would be most appreciated. Thank you.
You get the same behavior as auto increment in for instance MySQL with this
one: http://software-lab.de/doc/refG.html#genKey
I use it a lot in the VizReader code.
I'm not so sure I would've used it much though if I had know about the (id)
function from the start: http://software-lab.de/doc/refI.html#id
In my case it's all about displaying a nice id that is easy to relate for
humans and JavaScript in my non-traditional gui and as you can see both
approaches accomplish that but that latter is imo more elegant.
/Henrik Sarvell
(Copied verbatim form Henrik Sarvells' answer.)