Generating a Vector of Difference Between Two Vectors

generating a vector of difference between two vectors

You are looking for the function setdiff

setdiff(vectorB$id, vectorA$id)

If you did not want this reduced to unique values, you could create a not in function

(kudos to @joran here Match with negation)

'%nin%' <- Negate('%in%')

vectorB$id[vectorB$id %nin% vectorA$id]

Difference between two vectors in R

You can use setdiff

setdiff(b,a)
#[1] 2 6 8

Find the difference between all values of two vectors

sapply(a, "-", b)
#      [,1] [,2] [,3] [,4] [,5]
# [1,]    0    1    2    3    4
# [2,]   -1    0    1    2    3
# [3,]   -2   -1    0    1    2
# [4,]   -3   -2   -1    0    1
# [5,]   -4   -3   -2   -1    0
# [6,]   -5   -4   -3   -2   -1
# [7,]   -6   -5   -4   -3   -2
# [8,]   -7   -6   -5   -4   -3
# [9,]   -8   -7   -6   -5   -4
#[10,]   -9   -8   -7   -6   -5

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Explanation

Taking advantage of the fact that a scalar minus a vector in R is an element-wise subtraction between said scalar and each element of the vector, we can simply apply the minus - operator to each value in a against the whole vector b.

How to compare 2 vectors and create a separate vector based on the comparison

If, as in your example, the ranges are sorted then you can use std::set_symmetric_difference. It will return all elements that are not shared between the two ranges. Using you example you would use

std::set_symmetric_difference(v1.begin(), v1.end(), v2.begin(), v2.end(), std::back_inserter(v3));

So putting it all together we have

int main()
{
    std::vector<int> v1 = { 1,2,3,4,5,6,7,8,9 };
    std::vector<int> v2 = { 1,2,6 };
    std::vector<int> v3; //V3 should equal = {3,4,5,7,8,9}.

    std::set_symmetric_difference(v1.begin(), v1.end(), v2.begin(), v2.end(), std::back_inserter(v3));

    for (auto e : v3)
        std::cout << e << " ";

    return 0;
}

Output:

3 4 5 7 8 9

Live example

Comparing two vectors and calculating differences to corresponding elements

Calculate the difference between each element to get the time in the corresponding state and then sum over the times ordered by state.

state <- c(0, 1, 0, 1, 2, 1, 0, 1, 2, 3)
time <- c(0.00, 0.03, 0.12, 0.78, 0.87, 0.94, 0.97, 1.18, 1.23, 1.30)

df <- data.frame(state=state,time=time)
df$diff <- c(diff(df$time),0)

tim.p.state <- data.frame(time=sapply(split(df,df$state),function(df){return(sum(df$diff))}))
tim.p.state$proportion <- tim.p.state$time/time[length(time)]

How to generate a random vector between two vectors?

import random
vec3 = vec1 + random.uniform(0, 1) * (vec2 - vec1)

C++ get the difference between two vectors

//from cppreference
#include <iostream>
#include <algorithm>
#include <vector>
#include <iterator>
 
int main() {
 
    std::vector<int> v1 {1,1,2,3,3,4,5,5,6};
    std::vector<int> v2 {1,2,3,4,5,6};
    std::vector<int> diff;
    //no need to sort since it's already sorted
    //but you can sort with:
    //std::sort(std::begin(v1), std::end(v1))

    std::set_difference(v1.begin(), v1.end(), v2.begin(), v2.end(),
        std::inserter(diff, diff.begin()));
 
    for (auto i : v1) std::cout << i << ' ';
    std::cout << "minus ";
    for (auto i : v2) std::cout << i << ' ';
    std::cout << "is: ";
 
    for (auto i : diff) std::cout << i << ' ';
    std::cout << '\n';
}

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