Code Review Notes 47.8% of your time is spent in GC. 1.5G is allocated on the heap (!) The repa code looks a lot more complicated than the list code. Lots of parallel GC is occuring I can get up to 300% efficiency on a -N4 machine Putting in more type signatures will make it … Read more
Finally I found the answer to my question with the help of some ideas from @larsmans and @eickenberg. The problem was that X_train did not have the same number of elements in all the arrays. So, it was not able to form a 2D array. Now that I have added an additional value to that … Read more
Basically in selection sort, swap that occurs at the end of each “round” can change the relative order of items having the same value. for example, suppose you sorted 4 2 3 4 1 with selection sort. the first “round” will go through each element looking for the minimum element. it will find that 1 … Read more
An Array{Bool} stores each true/false value as a Bool, which is represented internally as a UInt8. So if your array has N elements, it will take N bytes to store it. A BitArray stores each true/false value as a single bit, with (conceptually) 8 of them packed into a single UInt8. Consequently, it takes only … Read more
This has changed with Xcode 6 beta 3. While arrays used to be semi-mutable, as you describe, with their elements changeable but their length fixed, now immutable arrays share the same value semantics as Dictionaries: From the Xcode 6 beta 3 release notes: • Array in Swift has been completely redesigned to have full value … Read more
They both store data in a linear contiguous array where accessing or iterating is both an O(1) operation so there’s no difference in performance. The only case when vector is slower is probably for some small lists because array is stored on stack in the current stack frame, hence their data is highly probably already … Read more
Try var d = $($.map(c, function(el){return $.makeArray(el)})); Or var d = $($.map(c, function(el){return el.get();})); The demo.
As said by Akavall, arrays are hashable. That means they can be used as a key to a map. They are also pass by value. Each time you pass it to a function or assign it to another variable it makes a complete copy of it. They can be serialized by encoding/binary. They also can … Read more
O(N) Algorithm Initialize output array to all -1s. Create an empty stack of indexes of items we have visited in the input array but don’t yet know the answer for in the output array. Iterate over each element in the input array: Is it smaller than the item indexed by the top of the stack? … Read more
Of course, you can do it – it’s just len is not a field, it’s a method: fn test_length(arr: &[String]){ if arr.len() >= 10 { // Do stuff } } If you only started learning Rust, you should read through the official book – you will also find why &[str] does not make sense (in … Read more