indices

来源： https://stackoverflow.com/questions/9503510/how-to-invert-numpy-where-np-where-function

来源： https://stackoverflow.com/questions/60316727/got-fatal-error-index-out-of-range-show-index-in-list-item-for-swiftui

来源： https://stackoverflow.com/questions/60316727/got-fatal-error-index-out-of-range-show-index-in-list-item-for-swiftui

问题 my problem is: I have simple array with some Items. I want to display a List with these items using a ForEach with .indices() . (This is because my actual problem handles with Toggle in a List and for the isOn binding I need the index to address a model that is bound to an EnvironmentObject ). So the solution to loop over the array items is no possible solution for my problem. The simplified starting point looks like this: struct ContentView: View { @State var items = ["Item1", "Item2",

问题 How to perform a sum just for a list of indices over numpy array, e.g., if I have an array a = [1,2,3,4] and a list of indices to sum, indices = [0, 2] and I want a fast operation to give me the answer 4 because the value for summing value at index 0 and index 2 in a is 4 回答1: You can use sum directly after indexing with indices : a = np.array([1,2,3,4]) indices = [0, 2] a[indices].sum() 回答2: The accepted a[indices].sum() approach copies data and creates a new array, which might cause problem

问题 Say I have a list of object Person { public string Name {get; set;} public string Gender {get; set;} } What I want is to create a List that I can order by using a property called OrderIndex. So I add this property to the Person object: { public string Name {get; set;} public string Gender {get; set;} public int OrderIndex {get; set;} } The purpose of this OrderIndex property is to place the Person object in the list at a specific index for ranking the Person object higher. But I am very

问题 Say I have a list of object Person { public string Name {get; set;} public string Gender {get; set;} } What I want is to create a List that I can order by using a property called OrderIndex. So I add this property to the Person object: { public string Name {get; set;} public string Gender {get; set;} public int OrderIndex {get; set;} } The purpose of this OrderIndex property is to place the Person object in the list at a specific index for ranking the Person object higher. But I am very

问题 Considering the following : {-# LANGUAGE TemplateHaskell #-} import Control.Lens data Typex = Typex { _level :: Int , _coordinate :: (Int, Int) , _connections :: [(Int,(Int,Int))] } deriving Show makeLenses ''Typex initTypexLevel :: Int -> Int -> Int -> [Typex] initTypexLevel a b c = [ Typex a (x, y) [(0,(0,0))] | x <- [0..b], y <- [0..c] ] buildNestedTypexs :: [(Int, Int)] -> [[Typex]] buildNestedTypexs pts = setConnections [ initTypexLevel i y y | (i,(_,y)) <- zip [0..] pts ] setConnections

问题 Considering the following : {-# LANGUAGE TemplateHaskell #-} import Control.Lens data Typex = Typex { _level :: Int , _coordinate :: (Int, Int) , _connections :: [(Int,(Int,Int))] } deriving Show makeLenses ''Typex initTypexLevel :: Int -> Int -> Int -> [Typex] initTypexLevel a b c = [ Typex a (x, y) [(0,(0,0))] | x <- [0..b], y <- [0..c] ] buildNestedTypexs :: [(Int, Int)] -> [[Typex]] buildNestedTypexs pts = setConnections [ initTypexLevel i y y | (i,(_,y)) <- zip [0..] pts ] setConnections

问题 I want to solve something like the problem detailed at Find index mapping between two numpy arrays, but where the two arrays do not necessarily contain the same set of values, although their values are unique within each array, and are sorted. E.g. if I have two arrays: a = np.array([1.1, 2.2, 3.3, 4.4, 5.5]) b = np.array([2.2, 3.0, 4.4, 6.0]) I want to get an array of the same length as a which gives the index into b where the matching element is, or -1 if there is no match. I.e. in this