Questions tagged [persistent-data]
36 questions
9
votes
4 answers
Javascript functional library with persistent data structures
I'm looking for a functional library with persistent data structures. I only need nested arrays and dictionaries. There are some functional javascript libraries, but they are not geared towards immutability. I want to be able to write
var dict =…
Adam Schmideg
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8
votes
2 answers
Fitting a segment in a two-dimensional plane
I'm having troubles with the following problem
Given N x S grid and m segments parallel to the horizontal axis (all of them are tuples (x', x'', y)), answer Q online queries of form (x', x''). The answer to such a query is the smallest y (if there…
Y N
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5
votes
1 answer
Fully persistent linked list
Why isn't there any implementation (in C, C++, Java or even Python...) of a fully persistent (not necessarily functional) linked list that has a constant time/space overhead in the number of modifications?
The data structure I have in mind is the…
Issam T.
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4
votes
3 answers
Persistent data in a web app
What is the best way of storing persistent data ? I want to save the time the user was last active on the page.At first I used localstorage, then i switched to cookies because it seemed easier to use, now I'm thinking of storing it in a…
andrei
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3
votes
2 answers
Models with persistent state between HTTP requests
I want to create a web application with a model that persists between HTTP requests. From what I understand languages like PHP treat each HTTP request as a brand new connection except for some global variables like SESSION; so each time the user…
ace
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3
votes
1 answer
What's the fastest way to calculate log of a power of 32?
Given that the language is javascript, and that the input is < 1073741824, what's the fastest way to obtain the equivalent to:
Math.floor(Math.log(len) / Math.log(32))
I've tried with an if:
if (len < 1024) return 1;
if (len < 32768) return 2;
if…
BenG
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3
votes
1 answer
How to get the core data persistent store path in WatchKit Extension target
I developed a iOS app that uses Core Data framework and saves the persistent store in the application document directory.
Into the app terget I can retrieve the persistent store path using the following method:
- (NSString…
Magurizio
- 300
- 2
- 10
2
votes
2 answers
Django : make a variable persistent
Basically I want to make a variable persitent in Django and I don't know how.
To be more precise, I want a user to choose a specific project when he logs in the site (via a ChoiceField for example). Then, for as long as he does not select another…
Johanna
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2
votes
2 answers
How to put file manually to iOS persistentDataPath?
{to the point}
So I want to create some Quiz Game on Unity that the questions data using external file (in this case I using JSON). I want to keep my questions data can access/edit by myself separately. And then I just have to copy-paste it manually…
Shiro
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2
votes
2 answers
What exactly does this Standard ML code do?
I'm reading Chris Okasaki's purely functional data structures, and there's one example I am having trouble with. It is located here. In particular, I don't understand how the rotate and exec functions work:
fun rotate($Nil, y::_, a) = $Cons (y,…
Jason Baker
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2
votes
3 answers
Does anyone have or know of a persistent prefix trie available in F#?
The performance of F#'s Map and Set are pretty lacking for my particular application. It seems a nice prefix trie would step up performance in my interpreter a good bit, especially in terms of symbol lookups by name. The only caveats are that it…
Bryan Edds
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1
vote
2 answers
Persistent variable on iframe?
I have a
being dynamically created, and it contains an