I had the same exact issue. What I did was the following: struct ContentView: View { @State var didAppear = false @State var appearCount = 0 var body: some View { Text(“Appeared Count: \(appearrCount)” .onAppear(perform: onLoad) } func onLoad() { if !didAppear { appearCount += 1 //This is where I loaded my coreData information into … Read more
Solution: member(X, [Y|T]) :- X = Y; member(X, T). Demonstration: ?- member(a, []). fail. ?- member(a, [a]). true ; fail. ?- member(a, [b]). fail. ?- member(a, [1, 2, 3, a, 5, 6, a]). true ; true ; fail. How it works: We are looking for an occurrence of the first argument, X, in the the … Read more
EDIT As of groovy 1.8.6 you can use the collate method on lists def origList = [1, 2, 3, 4, 5, 6, 7, 8, 9] assert [[1, 2, 3, 4], [5, 6, 7, 8], [9]] == origList.collate(4) Another method using inject and metaClasses List.metaClass.partition = { size -> def rslt = delegate.inject( [ [] ] … Read more
The primary difference is that quote prevents evaluation of the elements, whereas list does not: user=> ‘(1 2 (+ 1 2)) (1 2 (+ 1 2)) user=> (list 1 2 (+ 1 2)) (1 2 3) For this reason (among others), it is idiomatic clojure to use a vector when describing a literal collection: user=> … Read more
gatoatigrado’s answer gives some nice advice for measuring the performance of various solutions. Here is a more symbolic answer. I think solution 0 (or, exactly equivalently, solution 4) will be the fastest. Remember that Haskell is lazy, so map will not have to construct the whole list before and is applied. A good way to … Read more
A quick search on Hoogle showed that there is no such function. On the other hand, it was replied that there is one in the split package, called chunksOf. However, you can do it on your own group :: Int -> [a] -> [[a]] group _ [] = [] group n l | n > … Read more
First, not all S-expressions represent lists; an expression such as foobar, representing a bare atom, is also considered an S-expression. As is the “cons cell” syntax, (car . cons), used when the “cons” part is not itself another list (or nil). The more familiar list expression, such as (a b c d), is just syntactic … Read more
If you need that the element is exactly one: t.filter { it.retailerId == value }.size == 1 if not: t.any { it.retailerId == value } With foldRight and a break when you found it: t.foldRight(false) {val, res -> if(it.retailerId == value) { return@foldRight true } else { res } }
Use isdir field of dir output to separate subdirectories and files: d = dir(pathFolder); isub = [d(:).isdir]; %# returns logical vector nameFolds = {d(isub).name}’; You can then remove . and .. nameFolds(ismember(nameFolds,{‘.’,’..’})) = []; You shouldn’t do nameFolds(1:2) = [], since dir output from root directory does not contain those dot-folders. At least on Windows.
You could go “UNIX style” and use the shuf command from the coreutils package: :10,20!shuf<CR>