vector Questions
16
Solved
Suppose I have a std::vector (let's call it myVec) of size N. What's the simplest way to construct a new vector consisting of a copy of elements X through Y, where 0 <= X <= Y <= N-1? For ...
10
Solved
I know the size of a vector, which is the best way to initialize it?
Option 1:
vector<int> vec(3); //in .h
vec.at(0)=var1; //in .cpp
vec.at(1)=var2; //in .cpp
vec.at(2)=var3; //in .cpp
Op...
2
Solved
I saw this video on YouTube: https://www.youtube.com/watch?v=YQs6IC-vgmo
in which Bjarne says it is better to use vectors, rather than linked lists. I am unable to grasp the entire thing, so could ...
Muscid asked 9/12, 2015 at 4:10
8
Solved
I have a vector like this :
vector< vector<int> > myVector;
All row and column numbers are same in this vector.
I want to find row count and column count of this vector.
For row c...
12
Solved
I have a dataframe such as:
a1 = c(1, 2, 3, 4, 5)
a2 = c(6, 7, 8, 9, 10)
a3 = c(11, 12, 13, 14, 15)
aframe = data.frame(a1, a2, a3)
I tried the following to convert one of the columns to a vecto...
Jules asked 15/8, 2011 at 20:8
2
Solved
I would like a way to programmatically "deconstruct" a vector of variable-length vectors in Julia. I do not care about the resulting vector's order.
For example, suppose that my vector of...
5
How can I calculate the 1-norm of the difference of two vectors, ||a - b||_1 = sum(|a_i - b_i|) in Python?
a = [1,2,3,4]
b = [2,3,4,5]
||a - b||_1 = 4
9
Solved
I'm trying to compute the angle between two vectors.
I tried this, but it always returns zero:
public double GetAngle(Vector2 a, Vector2 b)
{
double angle = Math.Atan2(b.Y, b.X) - Math.Atan2(a.Y, ...
13
Solved
So, I have the following:
std::vector< std::vector <int> > fog;
and I am initializing it very naively like:
for(int i=0; i<A_NUMBER; i++)
{
std::vector <int> fogRow;
for(int...
Kipton asked 15/7, 2013 at 20:21
3
In an std::vector<T> the vector owns the allocated storage and it constructs Ts and destructs Ts. Regardless of T's class hierarchy, std::vector<T> knows that it has only created a T an...
Gurl asked 6/8, 2022 at 6:48
5
Solved
I want to create an array of 10 empty vectors in Rust, but [Vec::new(); 10] doesn't work as Vec doesn't implement Copy. How can I do this, and in more general terms how can I initialize a arr...
4
Solved
9
Solved
Here is my issue, lets say I have a std::vector with ints in it.
let's say it has 50,90,40,90,80,60,80.
I know I need to remove the second, fifth and third elements. I don't necessarily always kn...
16
Solved
The question's pretty self-explanatory really. I know vaguely about vectors in maths, but I don't really see the link to C++ vectors.
3
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I have a std::vector<std::unique_ptr<T>>. I would like to insert some nullptrs into the middle of this vector. I tried vec.insert(first, size, nullptr) but this obviously doesn’t work b...
2
Solved
I want to know when four Vector 3 positions intersect, as in the image, from point to point a1 to a2 and b1 to b2 if they intersect each other from each of their positions. Does anyone have any ide...
Allaallah asked 23/12, 2019 at 2:38
7
Solved
During a recent interview, I suggested using vector<pair<int,int>> over vector<vector<int>> since we only wanted to store two values for every entry in the vector. I said so...
4
I have a problem with the following code:
Generator.h:
#pragma once
class Generator
{
public:
friend class BagObject;
Generator(void);
~Generator(void);
...
void generator(int);
private:
Bag...
Constrain asked 14/11, 2016 at 17:51
3
Solved
I have a vector containing n elements. I need to choose a subset of m elements randomly from the vector without repetition. What is the most efficient way of doing this? I need to do this several t...
7
Solved
I'm a C/Python programmer in C++ land working with the STL for the first time.
In Python, extending a list with another list uses the .extend method:
>>> v = [1, 2, 3]
>>> v_pri...
5
Solved
I have a direction vector that applied to a position gives me the point at which the camera should look. How can I get from that yaw, pitch and roll in order to use glRotatef properly?
Thanks in a...
6
Solved
I am trying to insert a string separated by spaces into an array of strings without using vector in C++. For example:
using namespace std;
int main() {
string line = "test one two three.";
strin...
5
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I am working in R and have a named list of character vectors. Each vector describes the genes present in a biological pathway.
Please see example below:
gene_sets = list(pathwayX= c("Gene3&quo...
5
Solved
I have this function:
void RegMatrix::MatrixInit(int numRow,int numCol, std::vector<double> fill)
{
do something;
}
and i want to send this:
MatrixInit(numRow,numCol,NULL);
how c...
8
Solved
How to check if a vector contains a given value?
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