collections

问题 Main question: What is the best way to perform safe publication of the contents of an array, collection, or map in Java? Here is what I've tried and some side questions I have: Side question #1 On thread 1, I'm writing to an HashMap: Map<K, V> map = new HashMap<>(); map.put(key, value); My current understanding is that: Collections.unmodifiableMap() does not constitute safe publication of the references stored in the map. By examining these particular implementations of Map.of(), the result

问题 Is it possible to collect an iterator such that it populates a collection backwards, such as using push_front in a VecDeque ? It's possible to collect into a Vec and then reverse it, but it seems like it should be unnecessary with data structures explicitly supporting this capability. I'd like to avoid writing an explicit for loop if possible. 回答1: Yes, it's possible: use std::collections::VecDeque; fn main() { let v: VecDeque<_> = (0..=2).collect_rev(); assert_eq!(v, [2, 1, 0]); let v: Vec<_

问题 I have a collection outcome resulting from the function: Counter(df.email_address) it returns each individual email address with the count of its repetitions. Counter({nan: 1618, 'store@kiddicare.com': 265, 'testorders@worldstores.co.uk': 1}) what I want to do is to use it as if it was a dictionary and create a pandas dataframe out of it with two columns one for email addresses and one for the value associated. I tried with: dfr = repeaters.from_dict(repeaters, orient='index') but i got the

问题 I'm trying to remove elements from a Clojure vector: Note that I'm using Clojure's operations from Kotlin val set = PersistentHashSet.create("foo") val vec = PersistentVector.create("foo", "bar") val seq = clojure.`core$remove`.invokeStatic(set, vec) as ISeq val resultVec = clojure.`core$vec`.invokeStatic(seq) as PersistentVector This is the equivalent of the following Clojure code: (remove #{"foo"} ["foo" "bar"]) The code works fine but I've noticed that creating a vector from the seq is

问题 I'm trying to remove elements from a Clojure vector: Note that I'm using Clojure's operations from Kotlin val set = PersistentHashSet.create("foo") val vec = PersistentVector.create("foo", "bar") val seq = clojure.`core$remove`.invokeStatic(set, vec) as ISeq val resultVec = clojure.`core$vec`.invokeStatic(seq) as PersistentVector This is the equivalent of the following Clojure code: (remove #{"foo"} ["foo" "bar"]) The code works fine but I've noticed that creating a vector from the seq is

问题 I have an application , which operates on the hashmap at stages , in the sense it adds/deletes/modifies keys in different classes . Thought of creating wrapper class by extending the Map class . And Hacking the predefined put and remove methods . STAGE 1 : HashMap<String, String> hashMap = new HashMap<>(); hashMap.put("Key1","Value1"); hashMap.put("Key2","Value2"); hashMap.put("Key3","Value3"); hashMap.put("Key4", "Value4"); Desired Result : Added: Key1 : Value1 Key2 : Value2 Key3 : Value3

问题 I'm developing a back end in meteor, now I'm trying to associate a text file with images, in some way. Is there a way to storage text files in a fscollection ? How can I associate them in two different collections? These are my two collections: Images = new FS.Collection("Images", { stores: [new FS.Store.FileSystem("Images", {path: "~/padonde/uploads"})] }); Reynosa = new Mongo.Collection("Reynosa"); In the FsCollection, I storage images and in the other collection storage data, but both of

问题 I'm developing a back end in meteor, now I'm trying to associate a text file with images, in some way. Is there a way to storage text files in a fscollection ? How can I associate them in two different collections? These are my two collections: Images = new FS.Collection("Images", { stores: [new FS.Store.FileSystem("Images", {path: "~/padonde/uploads"})] }); Reynosa = new Mongo.Collection("Reynosa"); In the FsCollection, I storage images and in the other collection storage data, but both of

问题 Is there a way to check if a current page belongs to a collection? If so, can I check what’s the label of the collection? Background story: What I’m trying to achieve is to display a different layout for all pages that belong to a collection. With this new layout I want to display a side navigation (some sort of „See also”) with listing of all pages in the collection that the current site belongs to. In case my question turns out to be dumb – forgive me, I’m new to jekyll and I really tried

问题 Is there a way to check if a current page belongs to a collection? If so, can I check what’s the label of the collection? Background story: What I’m trying to achieve is to display a different layout for all pages that belong to a collection. With this new layout I want to display a side navigation (some sort of „See also”) with listing of all pages in the collection that the current site belongs to. In case my question turns out to be dumb – forgive me, I’m new to jekyll and I really tried