Questions tagged [vec]
78 questions
0
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1 answer
Vulkan unpack uvec4 from integer
I've observed some strange behavior. I have an array of unsigned 32bit integers.
I use one integer to encode 4 values, each one byte in size. I'd like to then pass such buffer to vertex shader
layout (location = 0) in uvec4 coords;
In order to…
alagris
- 1,838
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0
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2 answers
how to push into a vector a variable's resource but keep it alive
I got a question about how to move a variable into a vector but without destroying this variable because it has to be reused in a loop. Below shows what I mean:
type Letter = char;
type LetterSet = Vec;
fn main() {
let mut v =…
foehn
- 431
- 4
- 13
0
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2 answers
How to send to a tokio oneshot::channel when the Sender is in a Vec?
I want to use a container to manage tokio::oneshot::Senders. I'm using a Vec, but seems that values saved in Vec are references and I need to use self, not a reference, to call it:
use bytes::BytesMut;
use tokio::sync::oneshot;
#[derive(Clone)]
pub…
Harlan Chen
- 321
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0
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1 answer
Holding a sorted array - reverse sorted inputs case
I get integers from the user (one by one) and insert into a sorted vec to its right place by running binary search and finding the insertion index.
The problem is when user decides to provide a reversed sorted input (one by one) then insertion will…
Renya Karasuma
- 1,044
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- 18
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1 answer
How to group the elements of a collection into all combinations of N parts?
I have encountered a problem that looks simple but is actually difficult. It appears to be a subset of a combined algorithm. is there a faster and more direct algorithm?
/// split the group {v1} to {n} parts
///
/// For example:
/// Group(here…
Anunaki
- 763
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- 18
0
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1 answer
Agda list last of a generic list of naturals concatenated with a list of 1
I have the function:
natListLast : List ℕ → ℕ
natListLast [] = 0
natListLast nats@(x ∷ xs) = v.last (v.fromList nats)
When I do
_ : natListLast (2 l.∷ l.[] l.++ 1 l.∷ l.[]) ≡ 1
_ = refl
I don't get any error.
But when I try to…
fsuna064
- 195
- 1
- 7
0
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1 answer
Agda: proof about `Vec` `last` using `with`
I'm trying to prove the following statement
vecNat : ∀ {n} (xs : Vec ℕ n) → last (xs ∷ʳ 1) ≡ 1
But I get confused the (x ∷ xs) case.
vecNat5 : ∀ {n} (xs : Vec ℕ n) → last (xs ∷ʳ 1) ≡ 1
vecNat5 [] = refl
vecNat5 (x ∷ xs) = {! 0!}
The goal…
fsuna064
- 195
- 1
- 7
0
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0 answers
How do I get a slice containing all but the Nth element?
I would like to get a slice of references from a vector which contains all but the Nth element. In my specific case, I would like a mutable reference to the Nth element and non-mutable references to all other elements.
I've got something that works…
Chuck
- 431
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- 10
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0 answers
How do I push an object which implements a trait with a trait parameter into a Vec?
I am trying to push an object which implements a trait with a trait parameter into a Vec:
trait IRequest {}
trait IRequestHandler
where
T: IRequest,
{
fn handle(&self, request: T);
}
pub struct CreateTodoRequest();
impl IRequest for…
0
votes
2 answers
Is there a way to convert Armadillo vector to a string in C++?
I was wondering if there is a way to convert an Armadillo vector to a std string. For example if I have this vector:
arma::vec myvec("1 2 3"); //create a vector of length 3
How can I produce:
std::string mystring("1 2 3");
from it?
Cinnamon
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- 4
0
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1 answer
Why can I create boxed iterator from Vec and not from array?
The code below compiles, but if the 'args' passed to the function 'f' is changed from a Vec to an array of Strings it does not. I'm trying to understand why. I assume it has something to do with the ownership rules, but I could use some…
Bill Barrington
- 178
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votes
1 answer
I'm adding a "templated non-member function" to a .h file. Why isn't my program outputting anything after I've added the code below:
//this function is takes in two arguments, a vector of type Vec and an element of type T, and returns //the number of elements that matched the argument and were successfully removed from the vector. The //order of the other elements should stay the…
nzaw96
- 1
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0 answers
What is the canonical way to implement methods on Vec?
I have some struct Animal. I want to implement some methods on Vec. I believe the correct way to do this is to create a new wrapper object called Animals. What is the correct object to make this wrapper, though? A struct? An enum? Something…
trexinf14s
- 261
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0
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1 answer
pretty printing a Vec with a separator
I am trying to apply join (or something similar) to a Vec in order to pretty print it.
What I came up with so far is this (and this does what I want):
let vec: Vec = "abcdef".chars().collect();
let sep = "-";
let vec_str: String = vec
…
hiro protagonist
- 44,693
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0
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2 answers
Collecting to a Vec vs &Vec
I have the following code-snippets (don't question the sense of them ;) )
1. get the n-th element of a Vec recursively
fn helper(n: usize, current_n: usize, current_xs: &Vec, accumulator: Option) -> Option {
if current_n > n…
SleepyX667
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