My issue here is that I want to index on "complex" values. I was under the impression ES6 maps solve amongst others the problem that with objects - keys are only strings.
I want to index on 2 (or 100) properties - in this example the x and y values. I don't want to iterate the whole collection and all the keys every time I check for existence - that's very inefficient. Moreover, I don't want to write a for loop over the entries every time I check for existence - if I wanted that I'd just use an array. Also note, we're talking about the _keys_ of the map and _not_ the values. BTW in Python (which I reiterate is just an example) it's done via a hash function ( https://github.com/python-git/python/blob/master/Objects/tupleobject.c#L290) that's not the issue though. On Mon, Feb 17, 2014 at 11:43 PM, Bradley Meck <[email protected]>wrote: > I understand the capability of python, but that is done through > comprehensions that do not relate to the mapping of key to value. > In ES6 the syntax comes out to: > > ``` > let tuple = {x:3,y:5} > [for (value of map.entries()) if > (Object.keys(tuple).every((tupleKey)=>tuple[tupleKey] == value[tupleKey])) > value] > ``` > > A quick comparator function for tuple like objects would be more clear > than comprehension that does not relate to the mapping of key to value. > Notice how the keys of `map` are never used in the comprehension. > > > On Mon, Feb 17, 2014 at 3:35 PM, Benjamin (Inglor) Gruenbaum < > [email protected]> wrote: > >> Hi, when you reply please reply to the list (that is, include esdiscuss >> in the list of recipients) - otherwise I'm the only one who can read your >> mail. >> >> As for your question, You might want to look into how maps (or >> dictionaries) work in languages like Python where you can have a dictionary >> with tuple keys for example which would let me index on `(x,y)` values. >> This is of course a very 'simplified' example of what I'm actually doing >> (statistical learning). >> >> >> On Mon, Feb 17, 2014 at 11:31 PM, Bradley Meck <[email protected]>wrote: >> >>> What you are describing is a Set/Array of data that runs a filter at >>> runtime. Could you go into some detail on why a filter on sets/arrays does >>> not make sense for your use case? I am unsure what the original mapping of >>> key (during .set(key, value)) to value would represent if keys are treated >>> as many-many filters rather than 1-1 relationships for Maps in ES6. >>> >> >> >
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