25 Rewriting R code in C++
25.1 Getting started with C++ (Exercises 25.2.6)
Q1. With the basics of C++ in hand, it’s now a great time to practice by reading and writing some simple C++ functions. For each of the following functions, read the code and figure out what the corresponding base R function is. You might not understand every part of the code yet, but you should be able to figure out the basics of what the function does.
#include <Rcpp.h>
using namespace Rcpp;
// [[Rcpp::export]]
double f1(NumericVector x) {
int n = x.size();
double y = 0;
for(int i = 0; i < n; ++i) {
y += x[i] / n;
}
return y;
}
// [[Rcpp::export]]
NumericVector f2(NumericVector x) {
int n = x.size();
NumericVector out(n);
out[0] = x[0];
for(int i = 1; i < n; ++i) {
out[i] = out[i - 1] + x[i];
}
return out;
}
// [[Rcpp::export]]
bool f3(LogicalVector x) {
int n = x.size();
for(int i = 0; i < n; ++i) {
if (x[i]) return true;
}
return false;
}
// [[Rcpp::export]]
int f4(Function pred, List x) {
int n = x.size();
for(int i = 0; i < n; ++i) {
LogicalVector res = pred(x[i]);
if (res[0]) return i + 1;
}
return 0;
}
// [[Rcpp::export]]
NumericVector f5(NumericVector x, NumericVector y) {
int n = std::max(x.size(), y.size());
NumericVector x1 = rep_len(x, n);
NumericVector y1 = rep_len(y, n);
NumericVector out(n);
for (int i = 0; i < n; ++i) {
out[i] = std::min(x1[i], y1[i]);
}
return out;
}A1.
f1() is the same as mean():
f2() is the same as cumsum():
f3() is the same as any():
x1 <- c(TRUE, FALSE, FALSE, TRUE)
x2 <- c(FALSE, FALSE)
f3(x1)
#> [1] TRUE
any(x1)
#> [1] TRUE
f3(x2)
#> [1] FALSE
any(x2)
#> [1] FALSEf4() is the same as Position():
f5() is the same as pmin():
v1 <- c(1, 3, 4, 5, 6, 7)
v2 <- c(1, 2, 7, 2, 8, 1)
f5(v1, v2)
#> [1] 1 2 4 2 6 1
pmin(v1, v2)
#> [1] 1 2 4 2 6 1Q2. To practice your function writing skills, convert the following functions into C++. For now, assume the inputs have no missing values.
diff(). Start by assuming lag 1, and then generalise for lagn.var(). Read about the approaches you can take on Wikipedia. Whenever implementing a numerical algorithm, it’s always good to check what is already known about the problem.
A2. The performance benefits are not going to be observed if the function is primitive since those are already tuned to the max in R for performance. So, expect performance gain only for diff() and var().
is.primitive(all)
#> [1] TRUE
is.primitive(cumprod)
#> [1] TRUE
is.primitive(diff)
#> [1] FALSE
is.primitive(range)
#> [1] TRUE
is.primitive(var)
#> [1] FALSE#include <vector>
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
bool allC(std::vector<bool> x)
{
for (const auto& xElement : x)
{
if (!xElement) return false;
}
return true;
}
v1 <- rep(TRUE, 10)
v2 <- c(rep(TRUE, 5), rep(FALSE, 5))
all(v1)
#> [1] TRUE
allC(v1)
#> [1] TRUE
all(v2)
#> [1] FALSE
allC(v2)
#> [1] FALSE
# performance benefits?
bench::mark(
all(c(rep(TRUE, 1000), rep(FALSE, 1000))),
allC(c(rep(TRUE, 1000), rep(FALSE, 1000))),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min
#> <bch:expr> <bch:tm>
#> 1 all(c(rep(TRUE, 1000), rep(FALSE, 1000))) 6.2µs
#> 2 allC(c(rep(TRUE, 1000), rep(FALSE, 1000))) 7.95µs
#> median `itr/sec` mem_alloc `gc/sec`
#> <bch:tm> <dbl> <bch:byt> <dbl>
#> 1 6.55µs 148148. 15.8KB 0
#> 2 8.31µs 116089. 15.8KB 0#include <vector>
// [[Rcpp::export]]
std::vector<double> cumprodC(const std::vector<double> &x)
{
std::vector<double> out{x};
for (std::size_t i = 1; i < x.size(); i++)
{
out[i] = out[i - 1] * x[i];
}
return out;
}
v1 <- c(10, 4, 6, 8)
cumprod(v1)
#> [1] 10 40 240 1920
cumprodC(v1)
#> [1] 10 40 240 1920
# performance benefits?
bench::mark(
cumprod(v1),
cumprodC(v1),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt>
#> 1 cumprod(v1) 90ns 100ns 8587187. 0B
#> 2 cumprodC(v1) 701ns 742ns 1213009. 4.12KB
#> `gc/sec`
#> <dbl>
#> 1 0
#> 2 0cumminC()
#include <vector>
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
std::vector<double> cumminC(const std::vector<double> &x)
{
std::vector<double> out{x};
for (std::size_t i = 1; i < x.size(); i++)
{
out[i] = (out[i] < out[i - 1]) ? out[i] : out[i - 1];
}
return out;
}
v1 <- c(3:1, 2:0, 4:2)
cummin(v1)
#> [1] 3 2 1 1 1 0 0 0 0
cumminC(v1)
#> [1] 3 2 1 1 1 0 0 0 0
# performance benefits?
bench::mark(
cummin(v1),
cumminC(v1),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc `gc/sec`
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt> <dbl>
#> 1 cummin(v1) 101ns 121ns 5946320. 0B 0
#> 2 cumminC(v1) 771ns 947ns 1003658. 4.12KB 0cummaxC()
#include <vector>
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
std::vector<double> cummaxC(const std::vector<double> &x)
{
std::vector<double> out{x};
for (std::size_t i = 1; i < x.size(); i++)
{
out[i] = (out[i] > out[i - 1]) ? out[i] : out[i - 1];
}
return out;
}
v1 <- c(3:1, 2:0, 4:2)
cummax(v1)
#> [1] 3 3 3 3 3 3 4 4 4
cummaxC(v1)
#> [1] 3 3 3 3 3 3 4 4 4
# performance benefits?
bench::mark(
cummax(v1),
cummaxC(v1),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc `gc/sec`
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt> <dbl>
#> 1 cummax(v1) 110ns 206ns 4775316. 0B 0
#> 2 cummaxC(v1) 782ns 982ns 968832. 4.12KB 0#include <vector>
#include <functional>
#include <algorithm>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
std::vector<double> diffC(const std::vector<double> &x, int lag)
{
std::vector<double> vec_start;
std::vector<double> vec_lagged;
std::vector<double> vec_diff;
for (std::size_t i = lag; i < x.size(); i++)
{
vec_lagged.push_back(x[i]);
}
for (std::size_t i = 0; i < (x.size() - lag); i++)
{
vec_start.push_back(x[i]);
}
std::transform(
vec_lagged.begin(), vec_lagged.end(),
vec_start.begin(), std::back_inserter(vec_diff),
std::minus<double>());
return vec_diff;
}
v1 <- c(1, 2, 4, 8, 13)
v2 <- c(1, 2, NA, 8, 13)
diff(v1, 2)
#> [1] 3 6 9
diffC(v1, 2)
#> [1] 3 6 9
diff(v2, 2)
#> [1] NA 6 NA
diffC(v2, 2)
#> [1] NA 6 NA
# performance benefits?
bench::mark(
diff(v1, 2),
diffC(v1, 2),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt>
#> 1 diff(v1, 2) 3.88µs 4.25µs 220833. 0B
#> 2 diffC(v1, 2) 1.06µs 1.14µs 821532. 0B
#> `gc/sec`
#> <dbl>
#> 1 0
#> 2 0#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
// [[Rcpp::export]]
std::vector<double> rangeC(std::vector<double> x)
{
std::vector<double> rangeVec{0.0, 0.0};
rangeVec.at(0) = *std::min_element(x.begin(), x.end());
rangeVec.at(1) = *std::max_element(x.begin(), x.end());
return rangeVec;
}
v1 <- c(10, 4, 6, 8)
range(v1)
#> [1] 4 10
rangeC(v1)
#> [1] 4 10
# performance benefits?
bench::mark(
range(v1),
rangeC(v1),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc `gc/sec`
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt> <dbl>
#> 1 range(v1) 2.49µs 2.79µs 325423. 0B 0
#> 2 rangeC(v1) 692.09ns 761.01ns 1006096. 4.12KB 0#include <vector>
#include <cmath>
#include <numeric>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
double variance(std::vector<double> x)
{
double sumSquared{0};
double mean = std::accumulate(x.begin(), x.end(), 0.0) / x.size();
for (const auto& xElement : x)
{
sumSquared += pow(xElement - mean, 2.0);
}
return sumSquared / (x.size() - 1);
}
v1 <- c(1, 4, 7, 8)
var(v1)
#> [1] 10
variance(v1)
#> [1] 10
# performance benefits?
bench::mark(
var(v1),
variance(v1),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt>
#> 1 var(v1) 5.46µs 6.57µs 133247. 0B
#> 2 variance(v1) 661.01ns 682.08ns 1208419. 4.12KB
#> `gc/sec`
#> <dbl>
#> 1 0
#> 2 025.2 Missing values (Exercises 25.4.5)
Q1. Rewrite any of the functions from Exercise 25.2.6 to deal with missing values. If na.rm is true, ignore the missing values. If na.rm is false, return a missing value if the input contains any missing values. Some good functions to practice with are min(), max(), range(), mean(), and var().
A1. We will only create a version of range() that deals with missing values. The same principle applies to others:
#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>
#include <Rcpp.h>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
std::vector<double> rangeC_NA(std::vector<double> x, bool removeNA = true)
{
std::vector<double> rangeVec{0.0, 0.0};
bool naPresent = std::any_of(
x.begin(),
x.end(),
[](double d)
{ return isnan(d); });
if (naPresent)
{
if (removeNA)
{
std::remove(x.begin(), x.end(), NAN);
}
else
{
rangeVec.at(0) = NA_REAL; // NAN;
rangeVec.at(1) = NA_REAL; // NAN;
return rangeVec;
}
}
rangeVec.at(0) = *std::min_element(x.begin(), x.end());
rangeVec.at(1) = *std::max_element(x.begin(), x.end());
return rangeVec;
}
v1 <- c(10, 4, NA, 6, 8)
range(v1, na.rm = FALSE)
#> [1] NA NA
rangeC_NA(v1, FALSE)
#> [1] NA NA
range(v1, na.rm = TRUE)
#> [1] 4 10
rangeC_NA(v1, TRUE)
#> [1] 4 10Q2. Rewrite cumsum() and diff() so they can handle missing values. Note that these functions have slightly more complicated behaviour.
A2. The cumsum() docs say:
An
NAvalue inxcauses the corresponding and following elements of the return value to beNA, as does integer overflow in cumsum (with a warning).
Similarly, diff() docs say:
NA’s propagate.
Therefore, both of these functions don’t allow removing missing values and the NAs propagate.
As seen from the examples above, diffC() already behaves this way.
Similarly, cumsumC() propagates NAs as well.
25.3 Standard Template Library (Exercises 25.5.7)
Q1. To practice using the STL algorithms and data structures, implement the following using R functions in C++, using the hints provided:
A1.
-
median.default()usingpartial_sort.
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
double medianC(std::vector<double> &x)
{
int middleIndex = static_cast<int>(x.size() / 2);
std::partial_sort(x.begin(), x.begin() + middleIndex, x.end());
// for even number of observations
if (x.size() % 2 == 0)
{
return (x[middleIndex - 1] + x[middleIndex]) / 2;
}
return x[middleIndex];
}
v1 <- c(1, 3, 3, 6, 7, 8, 9)
v2 <- c(1, 2, 3, 4, 5, 6, 8, 9)
median.default(v1)
#> [1] 6
medianC(v1)
#> [1] 6
median.default(v2)
#> [1] 4.5
medianC(v2)
#> [1] 4.5
# performance benefits?
bench::mark(
median.default(v2),
medianC(v2),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt>
#> 1 median.default(v2) 20.1µs 21.9µs 42419. 0B
#> 2 medianC(v2) 701.1ns 731ns 981867. 0B
#> `gc/sec`
#> <dbl>
#> 1 428.
#> 2 0#include <vector>
#include <unordered_set>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
std::vector<bool> matchC(const std::vector<double> &x, const std::vector<double> &table)
{
std::unordered_set<double> tableUnique(table.begin(), table.end());
std::vector<bool> out;
for (const auto &xElem : x)
{
out.push_back(tableUnique.find(xElem) != tableUnique.end() ? true : false);
}
return out;
}
x1 <- c(3, 4, 8)
x2 <- c(1, 2, 3, 3, 4, 4, 5, 6)
x1 %in% x2
#> [1] TRUE TRUE FALSE
matchC(x1, x2)
#> [1] TRUE TRUE FALSE
# performance benefits?
bench::mark(
x1 %in% x2,
matchC(x1, x2),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt>
#> 1 x1 %in% x2 901.17ns 1.16µs 834245. 0B
#> 2 matchC(x1, x2) 1.27µs 1.39µs 602735. 4.12KB
#> `gc/sec`
#> <dbl>
#> 1 0
#> 2 0-
unique()using anunordered_set(challenge: do it in one line!).
#include <unordered_set>
#include <vector>
#include <iostream>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
std::unordered_set<double> uniqueC(const std::vector<double> &x)
{
std::unordered_set<double> xSet(x.begin(), x.end());
return xSet;
}Note that these functions are not comparable. As far as I can see, there is no way to get the same output as the R version of the function using the unordered_set data structure.
We can make comparable version using set data structure:
#include <set>
#include <vector>
#include <iostream>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
std::set<double> uniqueC2(const std::vector<double> &x)
{
std::set<double> xSet(x.begin(), x.end());
return xSet;
}
v1 <- c(1, 3, 3, 6, 7, 8, 9)
unique(v1)
#> [1] 1 3 6 7 8 9
uniqueC2(v1)
#> [1] 1 3 6 7 8 9
# performance benefits?
bench::mark(
unique(v1),
uniqueC2(v1),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt>
#> 1 unique(v1) 2.21µs 2.56µs 355408. 0B
#> 2 uniqueC2(v1) 872.07ns 982.08ns 730827. 4.12KB
#> `gc/sec`
#> <dbl>
#> 1 0
#> 2 0#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
const double minC(const std::vector<double> &x)
{
return *std::min_element(x.begin(), x.end());
}
// [[Rcpp::export]]
const double maxC(std::vector<double> x)
{
return *std::max_element(x.begin(), x.end());
}
v1 <- c(3, 3, 6, 1, 9, 7, 8)
min(v1)
#> [1] 1
minC(v1)
#> [1] 1
# performance benefits?
bench::mark(
min(v1),
minC(v1),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc `gc/sec`
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt> <dbl>
#> 1 min(v1) 200ns 220ns 4077436. 0B 0
#> 2 minC(v1) 651ns 691ns 1348638. 4.12KB 0
max(v1)
#> [1] 9
maxC(v1)
#> [1] 9
# performance benefits?
bench::mark(
max(v1),
maxC(v1),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc `gc/sec`
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt> <dbl>
#> 1 max(v1) 200ns 236ns 3363563. 0B 0
#> 2 maxC(v1) 661ns 742ns 1171622. 4.12KB 0-
which.min()usingmin_element, orwhich.max()usingmax_element.
#include <vector>
#include <algorithm>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
int which_maxC(std::vector<double> &x)
{
int maxIndex = std::distance(x.begin(), std::max_element(x.begin(), x.end()));
// R is 1-index based, while C++ is 0-index based
return maxIndex + 1;
}
// [[Rcpp::export]]
int which_minC(std::vector<double> &x)
{
int minIndex = std::distance(x.begin(), std::min_element(x.begin(), x.end()));
// R is 1-index based, while C++ is 0-index based
return minIndex + 1;
}
v1 <- c(3, 3, 6, 1, 9, 7, 8)
which.min(v1)
#> [1] 4
which_minC(v1)
#> [1] 4
# performance benefits?
bench::mark(
which.min(v1),
which_minC(v1),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt>
#> 1 which.min(v1) 380ns 412ns 2263058. 0B
#> 2 which_minC(v1) 651ns 681ns 1353108. 4.12KB
#> `gc/sec`
#> <dbl>
#> 1 0
#> 2 0
which.max(v1)
#> [1] 5
which_maxC(v1)
#> [1] 5
# performance benefits?
bench::mark(
which.max(v1),
which_maxC(v1),
iterations = 100
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt>
#> 1 which.max(v1) 401ns 421ns 2108798. 0B
#> 2 which_maxC(v1) 661ns 726ns 1262594. 4.12KB
#> `gc/sec`
#> <dbl>
#> 1 0
#> 2 0-
setdiff(),union(), andintersect()for integers using sorted ranges andset_union,set_intersectionandset_difference.
Note that the following C++ implementations of given functions are not strictly equivalent to their R versions. As far as I can see, there is no way for them to be identical while satisfying the specifications mentioned in the question.
#include <algorithm>
#include <iostream>
#include <vector>
#include <set>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
std::set<int> unionC(std::vector<int> &v1, std::vector<int> &v2)
{
std::sort(v1.begin(), v1.end());
std::sort(v2.begin(), v2.end());
std::vector<int> union_vec(v1.size() + v2.size());
auto it = std::set_union(v1.begin(), v1.end(), v2.begin(), v2.end(), union_vec.begin());
union_vec.resize(it - union_vec.begin());
std::set<int> union_set(union_vec.begin(), union_vec.end());
return union_set;
}
v1 <- c(1, 4, 5, 5, 5, 6, 2)
v2 <- c(4, 1, 6, 8)
union(v1, v2)
#> [1] 1 4 5 6 2 8
unionC(v1, v2)
#> [1] 1 2 4 5 6 8#include <algorithm>
#include <iostream>
#include <vector>
#include <set>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
std::set<int> intersectC(std::vector<int> &v1, std::vector<int> &v2)
{
std::sort(v1.begin(), v1.end());
std::sort(v2.begin(), v2.end());
std::vector<int> union_vec(v1.size() + v2.size());
auto it = std::set_intersection(v1.begin(), v1.end(), v2.begin(), v2.end(), union_vec.begin());
union_vec.resize(it - union_vec.begin());
std::set<int> union_set(union_vec.begin(), union_vec.end());
return union_set;
}
v1 <- c(1, 4, 5, 5, 5, 6, 2)
v2 <- c(4, 1, 6, 8)
intersect(v1, v2)
#> [1] 1 4 6
intersectC(v1, v2)
#> [1] 1 4 6#include <algorithm>
#include <iostream>
#include <vector>
#include <set>
using namespace std;
// [[Rcpp::plugins(cpp11)]]
// [[Rcpp::export]]
std::set<int> setdiffC(std::vector<int> &v1, std::vector<int> &v2)
{
std::sort(v1.begin(), v1.end());
std::sort(v2.begin(), v2.end());
std::vector<int> union_vec(v1.size() + v2.size());
auto it = std::set_difference(v1.begin(), v1.end(), v2.begin(), v2.end(), union_vec.begin());
union_vec.resize(it - union_vec.begin());
std::set<int> union_set(union_vec.begin(), union_vec.end());
return union_set;
}25.4 Session information
sessioninfo::session_info(include_base = TRUE)
#> ─ Session info ───────────────────────────────────────────
#> setting value
#> version R version 4.5.1 (2025-06-13)
#> os Ubuntu 24.04.3 LTS
#> system x86_64, linux-gnu
#> ui X11
#> language (EN)
#> collate C.UTF-8
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#> date 2025-10-19
#> pandoc 3.8.2 @ /opt/hostedtoolcache/pandoc/3.8.2/x64/ (via rmarkdown)
#> quarto NA
#>
#> ─ Packages ───────────────────────────────────────────────
#> package * version date (UTC) lib source
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#> fastmap 1.2.0 2024-05-15 [1] RSPM
#> fs 1.6.6 2025-04-12 [1] RSPM
#> glue 1.8.0 2024-09-30 [1] RSPM
#> graphics * 4.5.1 2025-06-13 [3] local
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#> jquerylib 0.1.4 2021-04-26 [1] RSPM
#> jsonlite 2.0.0 2025-03-27 [1] RSPM
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#> lifecycle 1.0.4 2023-11-07 [1] RSPM
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#> Rcpp * 1.1.0 2025-07-02 [1] RSPM
#> rlang 1.1.6 2025-04-11 [1] RSPM
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#> stats * 4.5.1 2025-06-13 [3] local
#> stringi 1.8.7 2025-03-27 [1] RSPM
#> stringr 1.5.2 2025-09-08 [1] RSPM
#> tibble 3.3.0 2025-06-08 [1] RSPM
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#> utf8 1.2.6 2025-06-08 [1] RSPM
#> utils * 4.5.1 2025-06-13 [3] local
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#> withr 3.0.2 2024-10-28 [1] RSPM
#> xfun 0.53 2025-08-19 [1] RSPM
#> xml2 1.4.0 2025-08-20 [1] RSPM
#> yaml 2.3.10 2024-07-26 [1] RSPM
#>
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#> * ── Packages attached to the search path.
#>
#> ──────────────────────────────────────────────────────────