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Go Rust
1
Print a literal string on standard output
fmt.Println("Hello World")
println!("Hello World");
2
Loop to execute some code a constant number of times
for i := 0; i < 10; i++ {
	fmt.Println("Hello")
}
Alternative implementation:
fmt.Println(strings.Repeat("Hello\n", 10))
Alternative implementation:
for range 10 {
	fmt.Println("Hello")
}
for _ in 0..10 { println!("Hello"); }
Alternative implementation:
print!("{}", "Hello\n".repeat(10));
3
Like a function which doesn't return any value, thus has only side effects (e.g. Print to standard output)
func finish(name string) {
  fmt.Println("My job here is done. Good bye " + name)
}
Alternative implementation:
finish := func(name string) {
	fmt.Println("My job here is done. Good bye " + name)
}
fn finish(name: &str) {
    println!("My job here is done. Goodbye {}", name);
}
4
Create a function which returns the square of an integer
func square(x int) int {
  return x*x
}
fn square(x : u32) -> u32 { x * x }
5
Declare a container type for two floating-point numbers x and y
type Point struct {
    x, y float64
}
struct Point {
    x: f64,
    y: f64,
}
Alternative implementation:
struct Point(f64, f64);
6
Do something with each item x of the list (or array) items, regardless indexes.
for _, x := range items {
    doSomething(x)
}
for x in items {
	do_something(x);
}
Alternative implementation:
items.into_iter().for_each(|x| do_something(x));
7
Print each index i with its value x from an array-like collection items
for i, x := range items {
    fmt.Printf("Item %d = %v \n", i, x)
}
for (i, x) in items.iter().enumerate() {
    println!("Item {} = {}", i, x);
}
Alternative implementation:
items.iter().enumerate().for_each(|(i, x)| {
    println!("Item {} = {}", i, x);
})
8
Create a new map object x, and provide some (key, value) pairs as initial content.
x := map[string]int {"one": 1, "two": 2}
let mut x = BTreeMap::new();
x.insert("one", 1);
x.insert("two", 2);
Alternative implementation:
let x: HashMap<&str, i32> = [
    ("one", 1),
    ("two", 2),
].into_iter().collect();
9
The structure must be recursive because left child and right child are binary trees too. A node has access to children nodes, but not to its parent.
type BinTree struct {
	Label       valueType
	Left, Right *BinTree
}
Alternative implementation:
type BinTree[L any] struct {
	Label       L
	Left, Right *BinTree[L]
}
struct BinTree<T> {
    value: T,
    left: Option<Box<BinTree<T>>>,
    right: Option<Box<BinTree<T>>>,
}
10
Generate a random permutation of the elements of list x
for i := range x {
	j := rand.Intn(i + 1)
	x[i], x[j] = x[j], x[i]
}
Alternative implementation:
y := make([]T, len(x))
perm := rand.Perm(len(x))
for i, v := range perm {
	y[v] = x[i]
}
Alternative implementation:
rand.Shuffle(len(x), func(i, j int) {
	x[i], x[j] = x[j], x[i]
})
Alternative implementation:
for i := len(x) - 1; i > 0; i-- {
	j := rand.Intn(i + 1)
	x[i], x[j] = x[j], x[i]
}
Alternative implementation:
func shuffle[T any](x []T) {
	rand.Shuffle(len(x), func(i, j int) {
		x[i], x[j] = x[j], x[i]
	})
}
let mut rng = StdRng::new().unwrap();
rng.shuffle(&mut x);
Alternative implementation:
let mut rng = thread_rng();
x.shuffle(&mut rng);
Alternative implementation:
pub fn shuffle<T>(vec: &mut [T]) {
    let n = vec.len();
    for i in 0..(n - 1) {
        let j = rand() % (n - i) + i;
        vec.swap(i, j);
    }
}

pub fn rand() -> usize {
    RandomState::new().build_hasher().finish() as usize
}
11
The list x must be non-empty.
x[rand.Intn(len(x))]
Alternative implementation:
func pickT(x []T) T {
	return x[rand.Intn(len(x))]
}
Alternative implementation:
func pick[T any](x []T) T {
	return x[rand.Intn(len(x))]
}
x[rand::thread_rng().gen_range(0..x.len())]
Alternative implementation:
let mut rng = rand::thread_rng();
let choice = x.choose(&mut rng).unwrap();
12
Check if the list contains the value x.
list is an iterable finite container.
func Contains(list []T, x T) bool {
	for _, item := range list {
		if item == x {
			return true
		}
	}
	return false
}
Alternative implementation:
slices.Contains(list, x)
list.contains(&x);
Alternative implementation:
list.iter().any(|v| v == &x)
Alternative implementation:
(&list).into_iter().any(|v| v == &x)
Alternative implementation:
list.binary_search(&x).is_ok()
13
Access each key k with its value x from an associative array mymap, and print them.
for k, x := range mymap {
  fmt.Println("Key =", k, ", Value =", x)
}
for (k, x) in &mymap {
    println!("Key={key}, Value={val}", key=k, val=x);
}
14
Pick a random number greater than or equals to a, strictly inferior to b. Precondition : a < b.
func pick(a, b  float64)  float64 {
	return a + (rand.Float64() * (b-a))
}
thread_rng().gen_range(a..b);
15
Pick a random integer greater than or equals to a, inferior or equals to b. Precondition : a < b.
func pick(a,b int) int {
	return a + rand.Intn(b-a+1)
}
Alternative implementation:
func pick(a, b int) int {
	return a + rand.IntN(b-a+1)
}
fn pick(a: i32, b: i32) -> i32 {
    let between = Range::new(a, b);
    let mut rng = rand::thread_rng();
    between.ind_sample(&mut rng)
}
Alternative implementation:
Uniform::new_inclusive(a, b).sample(&mut rand::thread_rng())
16
Call a function f on every node of binary tree bt, in depth-first infix order
func (bt *BinTree) Dfs(f func(*BinTree)) {
	if bt == nil {
		return
	}
	bt.Left.Dfs(f)
	f(bt)
	bt.Right.Dfs(f)
}
Alternative implementation:
func (bt *BinTree[L]) Dfs(f func(*BinTree[L])) {
	if bt == nil {
		return
	}
	bt.Left.Dfs(f)
	f(bt)
	bt.Right.Dfs(f)
}
fn depthFirstTraverse<T>(bt: &mut BiTree<T>, f: fn(&mut BiTree<T>)) {
    if let Some(left) = &mut bt.left {
        depthFirstTraverse(left, f);
    }
    
    f(bt);
    
    if let Some(right) = &mut bt.right {
        depthFirstTraverse(right, f);
    }
}
17
The structure must be recursive. A node may have zero or more children. A node has access to its children nodes, but not to its parent.
type Tree struct {
	Key keyType
	Deco valueType
	Children []*Tree
}
Alternative implementation:
type Tree[L any] struct {
	Label    L
	Children []*Tree[L]
}
struct Node<T> {
  value: T,
  children: Vec<Node<T>>,
}
18
Call a function f on every node of a tree, in depth-first prefix order
func (t *Tree) Dfs(f func(*Tree)) {
	if t == nil {
		return
	}
	f(t)
	for _, child := range t.Children {
		child.Dfs(f)
	}
}
Alternative implementation:
func (t *Tree[L]) Dfs(f func(*Tree[L])) {
	if t == nil {
		return
	}
	f(t)
	for _, child := range t.Children {
		child.Dfs(f)
	}
}
pub struct Tree<V> {
    children: Vec<Tree<V>>,
    value: V
}

impl<V> Tree<V> {
    pub fn dfs<F: Fn(&V)>(&self, f: F) {
        self.dfs_helper(&f);
    }
    fn dfs_helper<F: Fn(&V)>(&self, f: &F) {
        (f)(&self.value);
        for child in &self.children {
            child.dfs_helper(f)
        }
    }
    // ...
}
19
Reverse the order of the elements of the list x.
This may reverse "in-place" and destroy the original ordering.
for i, j := 0, len(x)-1; i < j; i, j = i+1, j-1 {
	x[i], x[j] = x[j], x[i]
}
Alternative implementation:
func reverse[T any](x []T) {
	for i, j := 0, len(x)-1; i < j; i, j = i+1, j-1 {
		x[i], x[j] = x[j], x[i]
	}
}
Alternative implementation:
slices.Reverse(x)
let y: Vec<_> = x.into_iter().rev().collect();
Alternative implementation:
x.reverse();
20
Implement a function search which looks for item x in a 2D matrix m.
Return indices i, j of the matching cell.
Think of the most idiomatic way in the language to return the two values at the same time.
func search(m [][]int, x int) (bool, int, int) {
	for i := range m {
		for j, v := range m[i] {
			if v == x {
				return true, i, j
			}
		}
	}
	return false, 0, 0
}
fn search<T: Eq>(m: &Vec<Vec<T>>, x: &T) -> Option<(usize, usize)> {
    for (i, row) in m.iter().enumerate() {
        for (j, column) in row.iter().enumerate() {
            if *column == *x {
                return Some((i, j));
            }
        }
    }

    None
}
21
Swap the values of the variables a and b
a, b = b, a
std::mem::swap(&mut a, &mut b);
Alternative implementation:
let (a, b) = (b, a);
22
Extract the integer value i from its string representation s (in radix 10)
i, err  := strconv.Atoi(s) 
Alternative implementation:
i, err := strconv.ParseInt(s, 10, 0)
let i = s.parse::<i32>().unwrap();
Alternative implementation:
let i: i32 = s.parse().unwrap_or(0);
Alternative implementation:
let i = match s.parse::<i32>() {
  Ok(i) => i,
  Err(_e) => -1,
};
23
Given a real number x, create its string representation s with 2 decimal digits following the dot.
s := fmt.Sprintf("%.2f", x)
let s = format!("{:.2}", x);
24
Declare a new string s and initialize it with the literal value "ネコ" (which means "cat" in japanese)
s := "ネコ"
let s = "ネコ";
25
Share the string value "Alan" with an existing running process which will then display "Hello, Alan"
go func() {
	v := <-ch
	fmt.Printf("Hello, %v\n", v)
}()

ch <- "Alan"
let (send, recv) = channel();

thread::spawn(move || {
    loop {
        let msg = recv.recv().unwrap();
        println!("Hello, {:?}", msg);
    }  
});

send.send("Alan").unwrap();
26
Declare and initialize a matrix x having m rows and n columns, containing real numbers.
const m, n = 3, 4
var x [m][n]float64
Alternative implementation:
func make2D(m, n int) [][]float64 {
	buf := make([]float64, m*n)

	x := make([][]float64, m)
	for i := range x {
		x[i] = buf[:n:n]
		buf = buf[n:]
	}
	return x
}
Alternative implementation:
func make2D[T any](m, n int) [][]T {
	buf := make([]T, m*n)

	x := make([][]T, m)
	for i := range x {
		x[i] = buf[:n:n]
		buf = buf[n:]
	}
	return x
}
let mut x = vec![vec![0.0f64; N]; M];
Alternative implementation:
let mut x = [[0.0; N] ; M];
27
Declare and initialize a 3D array x, having dimensions boundaries m, n, p, and containing real numbers.
const m, n, p = 2, 2, 3
var x [m][n][p]float64
Alternative implementation:
func make3D(m, n, p int) [][][]float64 {
	buf := make([]float64, m*n*p)

	x := make([][][]float64, m)
	for i := range x {
		x[i] = make([][]float64, n)
		for j := range x[i] {
			x[i][j] = buf[:p:p]
			buf = buf[p:]
		}
	}
	return x
}
Alternative implementation:
func make3D[T any](m, n, p int) [][][]T {
	buf := make([]T, m*n*p)

	x := make([][][]T, m)
	for i := range x {
		x[i] = make([][]T, n)
		for j := range x[i] {
			x[i][j] = buf[:p:p]
			buf = buf[p:]
		}
	}
	return x
}
let x = vec![vec![vec![0.0f64; p]; n]; m];
Alternative implementation:
let x = [[[0.0f64; P]; N]; M];
28
Sort the elements of the list (or array-like collection) items in ascending order of x.p, where p is a field of the type Item of the objects in items.
type ItemPSorter []Item
func (s ItemPSorter) Len() int{ return len(s) }
func (s ItemPSorter) Less(i,j int) bool{ return s[i].p<s[j].p }
func (s ItemPSorter) Swap(i,j int) { s[i],s[j] = s[j],s[i] }

func sortItems(items []Item){
	sorter := ItemPSorter(items)
	sort.Sort(sorter)
}
Alternative implementation:
less := func(i, j int) bool {
	return items[i].p < items[j].p
}
sort.Slice(items, less)
Alternative implementation:
compare := func(a, b Item) int {
	return cmp.Compare(a.p, b.p)
}
slices.SortFunc(items, compare)
items.sort_by(|a,b| a.p.cmp(&b.p));
Alternative implementation:
items.sort_by_key(|x| x.p);
29
Remove i-th item from list items.
This will alter the original list or return a new list, depending on which is more idiomatic.
Note that in most languages, the smallest valid value for i is 0.
items = append(items[:i], items[i+1:]...)
Alternative implementation:
copy(items[i:], items[i+1:])
items[len(items)-1] = nil
items = items[:len(items)-1]
Alternative implementation:
items = slices.Delete(items, i, i+1)
items.remove(i)
30
Launch the concurrent execution of procedure f with parameter i from 1 to 1000.
Tasks are independent and f(i) doesn't return any value.
Tasks need not run all at the same time, so you may use a pool.
wg := sync.WaitGroup{}
wg.Add(1000)
for i := 1; i <= 1000; i++ {
	go func(j int) {
          f(j)
          wg.Done()
        }(i)
}
wg.Wait()
let threads: Vec<_> = (0..1000).map(|i| {
	thread::spawn(move || f(i))
}).collect();

for thread in threads {
	thread.join();
}
Alternative implementation:
(0..1000).into_par_iter().for_each(f);
31
Create the recursive function f which returns the factorial of the non-negative integer i, calculated from f(i-1)
func f(i int) int {
  if i == 0 {
    return 1
  }
  return i * f(i-1)
}
fn f(n: u32) -> u32 {
    if n < 2 {
        1
    } else {
        n * f(n - 1)
    }
}
Alternative implementation:
fn factorial(num: u64) -> u64 {
    match num {
        0 | 1 => 1,
        _ => factorial(num - 1) * num,
    }
}
32
Create function exp which calculates (fast) the value x power n.
x and n are non-negative integers.
func exp(x, n int) int {
	switch {
	case n == 0:
		return 1
	case n == 1:
		return x
	case n%2 == 0:
		return exp(x*x, n/2)
	default:
		return x * exp(x*x, (n-1)/2)
	}
}
fn exp(x: u64, n: u64) -> u64 {
    match n {
        0 => 1,
        1 => x,
        i if i % 2 == 0 => exp(x * x, n / 2),
        _ => x * exp(x * x, (n - 1) / 2),
    }     
}
Alternative implementation:
fn exp(x: u64, n: u32) -> u64 {
    x.pow(n)
}
33
Assign to the variable x the new value f(x), making sure that no other thread may modify x between the read and the write.
var lock sync.Mutex

lock.Lock()
x = f(x)
lock.Unlock()
let mut x = x.lock().unwrap();
*x = f(x);
34
Declare and initialize a set x containing unique objects of type T.
x := make(map[T]bool)
Alternative implementation:
x := make(map[T]struct{})
let x: HashSet<T> = HashSet::new();
35
Implement a function compose (A -> C) with parameters f (A -> B) and g (B -> C), which returns the composition function g ∘ f
func compose(f func(A) B, g func(B) C) func(A) C {
	return func(x A) C {
		return g(f(x))
	}
}
fn compose<'a, A, B, C, G, F>(f: F, g: G) -> Box<Fn(A) -> C + 'a>
	where F: 'a + Fn(A) -> B, G: 'a + Fn(B) -> C
{
	Box::new(move |x| g(f(x)))
}
Alternative implementation:
fn compose<A, B, C>(f: impl Fn(A) -> B, g: impl Fn(B) -> C) -> impl Fn(A) -> C {
    move |x| g(f(x))
}
36
Implement a function compose which returns composition function g ∘ f for any functions f and g having exactly 1 parameter.
func composeIntFuncs(f func(int) int, g func(int) int) func(int) int {
	return func(x int) int {
		return g(f(x))
	}
}
Alternative implementation:
func compose[T, U, V any](f func(T) U, g func(U) V) func(T) V {
	return func(x T) V {
		return g(f(x))
	}
}
fn compose<'a, A, B, C, G, F>(f: F, g: G) -> Box<Fn(A) -> C + 'a>
	where F: 'a + Fn(A) -> B, G: 'a + Fn(B) -> C
{
	Box::new(move |x| g(f(x)))
}
Alternative implementation:
fn compose<A, B, C>(f: impl Fn(A) -> B, g: impl Fn(B) -> C) -> impl Fn(A) -> C {
    move |x| g(f(x))
}
37
Transform a function that takes multiple arguments into a function for which some of the arguments are preset.
type PayFactory func(Company, *Employee, *Employee) Payroll

type CustomPayFactory func(*Employee) Payroll

func CurryPayFactory(pf PayFactory,company Company, boss *Employee) CustomPayFactory {
	return func(e *Employee) Payroll {
		return pf(company, boss, e)
	}
}
fn add(a: u32, b: u32) -> u32 {
    a + b
}

let add5 = move |x| add(5, x);
 
38
Find substring t consisting in characters i (included) to j (excluded) of string s.
Character indices start at 0 unless specified otherwise.
Make sure that multibyte characters are properly handled.
t := string([]rune(s)[i:j])
let t = s.graphemes(true).skip(i).take(j - i).collect::<String>();
Alternative implementation:
let t = s.substring(i, j);
Alternative implementation:
let mut iter = s.grapheme_indices(true);
let i_idx = iter.nth(i).map(|x|x.0).unwrap_or(0);
let j_idx = iter.nth(j-i).map(|x|x.0).unwrap_or(0);
let t = s[i_idx..j_idx];
39
Set the boolean ok to true if the string word is contained in string s as a substring, or to false otherwise.
ok := strings.Contains(s, word)
let ok = s.contains(word);
40
Declare a Graph data structure in which each Vertex has a collection of its neighbouring vertices.
type Vertex struct{
	Id int
	Label string
	Neighbours map[*Vertex]bool
}

type Graph []*Vertex
Alternative implementation:
type Graph[L any] []*Vertex[L]

type Vertex[L any] struct {
	Label      L
	Neighbours map[*Vertex[L]]bool
}
41
Create the string t containing the same characters as the string s, in reverse order.
The original string s must remain unaltered. Each character must be handled correctly regardless its number of bytes in memory.
runes := []rune(s)
for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
   runes[i], runes[j] = runes[j], runes[i]
}
t := string(runes)
Alternative implementation:
func reverse(s string) string {
	if len(s) <= 1 {
		return s
	}
	var b strings.Builder
	b.Grow(len(s))
	for len(s) > 0 {
		r, l := utf8.DecodeLastRuneInString(s)
		s = s[:len(s)-l]
		b.WriteRune(r)
	}
	return b.String()
}
Alternative implementation:
runes := []rune(s)
slices.Reverse(runes)
t := string(runes)
let t = s.chars().rev().collect::<String>();
Alternative implementation:
let t: String = s.chars().rev().collect();
42
Print each item v of list a which is not contained in list b.
For this, write an outer loop to iterate on a and an inner loop to iterate on b.
mainloop:
	for _, v := range a {
		for _, w := range b {
			if v == w {
				continue mainloop
			}
		}
		fmt.Println(v)
	}
'outer: for va in &a {
    for vb in &b {
        if va == vb {
            continue 'outer;
        }
    }
    println!("{}", va);
}
43
Look for a negative value v in 2D integer matrix m. Print it and stop searching.
mainloop:
	for i, line := range m {
		for _, v := range line {
			if v < 0 {
				fmt.Println(v)
				break mainloop
			}
		}
	}
'outer: for v in m {
    'inner: for i in v {
        if i < 0 {
            println!("Found {}", i);
            break 'outer;
        }
    }
}
44
Insert the element x at position i in the list s. Further elements must be shifted to the right.
s = append(s, 0)
copy(s[i+1:], s[i:])
s[i] = x
Alternative implementation:
s = slices.Insert(s, i, x)
s.insert(i, x);
45
Sleep for 5 seconds in current thread, before proceeding with the next instructions.
time.Sleep(5 * time.Second)
thread::sleep(time::Duration::from_secs(5));
46
Create the string t consisting of the 5 first characters of the string s.
Make sure that multibyte characters are properly handled.
t := s
r := []rune(s)
if len(r) > 5 {
	t = string(r[:5])
}
Alternative implementation:
i := 0
count := 0
for i = range s {
	if count >= 5 {
		break
	}
	count++
}
t := s
if count >= 5 {
	t = s[:i]
}
let t = s.char_indices().nth(5).map_or(s, |(i, _)| &s[..i]);
Alternative implementation:
let t = s.chars().take(5).collect::<String>();
47
Create string t consisting in the 5 last characters of string s.
Make sure that multibyte characters are properly handled.
t := string([]rune(s)[len([]rune(s))-5:])
Alternative implementation:
i := len(s)
for j := 0; i > 0 && j < 5; j++ {
	_, size := utf8.DecodeLastRuneInString(s[0:i])
	i -= size
}
t := s[i:]
let last5ch = s.chars().count() - 5;
let t: String = s.chars().skip(last5ch).collect();
Alternative implementation:
let s = "a̐éö̲\r\n";
let t = s.grapheme_indices(true).rev().nth(5).map_or(s, |(i,_)|&s[i..]);
48
Assign to variable s a string literal consisting in several lines of text, including newlines.
s := `Huey
Dewey
Louie`
let s = "line 1
line 2
line 3";
Alternative implementation:
let s = r#"Huey
Dewey
Louie"#;
49
Build list chunks consisting in substrings of the string s, separated by one or more space characters.
chunks := strings.Split(s, " ")
Alternative implementation:
chunks := strings.Fields(s)
let chunks: Vec<_> = s.split_whitespace().collect();
Alternative implementation:
let chunks: Vec<_> = s.split_ascii_whitespace().collect();
Alternative implementation:
let chunks: Vec<_> = s.split(' ').collect();
50
Write a loop that has no end clause.
for {
	// Do something
}
loop {
	// Do something
}
51
Determine whether the map m contains an entry for the key k
_, ok := m[k]
m.contains_key(&k)
52
Determine whether the map m contains an entry with the value v, for some key.
func containsValue(m map[K]T, v T) bool {
	for _, x := range m {
		if x == v {
			return true
		}
	}
	return false
}
Alternative implementation:
func containsValue[M ~map[K]V, K, V comparable](m M, v V) bool {
	for _, x := range m {
		if x == v {
			return true
		}
	}
	return false
}
let does_contain = m.values().any(|&val| *val == v);
53
Concatenate elements of string list x joined by the separator ", " to create a single string y.
y := strings.Join(x, ", ")
let y = x.join(", ");
54
Calculate the sum s of the integer list or array x.
s := 0
for _, v := range x {
	s += v
}
x.iter().sum()
Alternative implementation:
let s = x.iter().sum::<i32>();
55
Create the string representation s (in radix 10) of the integer value i.
s := strconv.Itoa(i)
Alternative implementation:
s := strconv.FormatInt(i, 10)
Alternative implementation:
s := fmt.Sprintf("%d", i)
let s = i.to_string();
Alternative implementation:
let s = format!("{}", i);
56
Fork-join : launch the concurrent execution of procedure f with parameter i from 1 to 1000.
Tasks are independent and f(i) doesn't return any value.
Tasks need not run all at the same time, so you may use a pool.
Wait for the completion of the 1000 tasks and then print "Finished".
var wg sync.WaitGroup
wg.Add(1000)
for i := 1; i <= 1000; i++ {
	go func(i int) {
		f(i)
		wg.Done()
	}(i)
}
wg.Wait()
fmt.Println("Finished")
let threads: Vec<_> = (0..1000).map(|i| thread::spawn(move || f(i))).collect();

for t in threads {
	t.join();
}
57
Create the list y containing the items from the list x that satisfy the predicate p. Respect the original ordering. Don't modify x in-place.
y := make([]T, 0, len(x))
for _, v := range x{
	if p(v){
		y = append(y, v)
	}
}
Alternative implementation:
n := 0
for _, v := range x {
	if p(v) {
		n++
	}
}
y := make([]T, 0, n)
for _, v := range x {
	if p(v) {
		y = append(y, v)
	}
}
Alternative implementation:
func filter[S ~[]T, T any](x S, p func(T) bool) S {
	var y S
	for _, v := range x {
		if p(v) {
			y = append(y, v)
		}
	}
	return y
}
Alternative implementation:
del := func(t *T) bool { return !p(t) }

y := slices.DeleteFunc(slices.Clone(x), del)
let y: Vec<_> = x.iter().filter(p).collect();
58
Create the string lines from the content of the file with filename f.
b, err := os.ReadFile(f)
if err != nil {
	// Handle error...
}
lines := string(b)
let mut file = File::open(f)?;
let mut lines = String::new();
file.read_to_string(&mut lines)?;
Alternative implementation:
let lines = fs::read_to_string(f).expect("Can't read file.");
59
Print the message "x is negative" to standard error (stderr), with integer x value substitution (e.g. "-2 is negative").
fmt.Fprintln(os.Stderr, x, "is negative")
eprintln!("{} is negative", x);
60
Assign to x the string value of the first command line parameter, after the program name.
x := os.Args[1]
let first_arg = env::args().skip(1).next();

let fallback = "".to_owned();
let x = first_arg.unwrap_or(fallback);
Alternative implementation:
let x = env::args().nth(1).unwrap_or("".to_string());
61
Assign to the variable d the current date/time value, in the most standard type.
d := time.Now()
let d = time::now();
Alternative implementation:
let d = SystemTime::now();
62
Set i to the first position of string y inside string x, if exists.

Specify if i should be regarded as a character index or as a byte index.

Explain the behavior when y is not contained in x.
i := strings.Index(x, y)
let i = x.find(y);
63
Assign to x2 the value of string x with all occurrences of y replaced by z.
Assume occurrences of y are not overlapping.
x2 := strings.Replace(x, y, z, -1)
Alternative implementation:
x2 := strings.ReplaceAll(x, y, z)
let x2 = x.replace(&y, &z);
64
Assign to x the value 3^247
x := new(big.Int)
x.Exp(big.NewInt(3), big.NewInt(247), nil)
let a = 3.to_bigint().unwrap();
let x = num::pow(a, 247);
65
From the real value x in [0,1], create its percentage string representation s with one digit after decimal point. E.g. 0.15625 -> "15.6%"
s := fmt.Sprintf("%.1f%%", 100.0*x)
let s = format!("{:.1}%", 100.0 * x);
66
Calculate the result z of x power n, where x is a big integer and n is a positive integer.
nb := big.NewInt(int64(n))
var z big.Int
z.Exp(x, nb, nil)
let z = num::pow(x, n);
67
Calculate binom(n, k) = n! / (k! * (n-k)!). Use an integer type able to handle huge numbers.
z := new(big.Int)
z.Binomial(n, k)
fn binom(n: u64, k: u64) -> BigInt {
    let mut res = BigInt::one();
    for i in 0..k {
        res = (res * (n - i).to_bigint().unwrap()) /
              (i + 1).to_bigint().unwrap();
    }
    res
}
68
Create an object x to store n bits (n being potentially large).
var x *big.Int = new(big.Int)
Alternative implementation:
x := make([]bool, n)
Alternative implementation:
x := make([]uint64, (n+63)/64)
let mut x = vec![false; n];
69
Use seed s to initialize a random generator.

If s is constant, the generator output will be the same each time the program runs. If s is based on the current value of the system clock, the generator output will be different each time.
r := rand.New(rand.NewSource(s))
Alternative implementation:
r := rand.New(rand.NewPCG(s, s))
let s = 32;
let mut rng = StdRng::seed_from_u64(s);
70
Get the current datetime and provide it as a seed to a random generator. The generator sequence will be different at each run.
r := rand.New(rand.NewSource(time.Now().UnixNano()))
let d = SystemTime::now()
    .duration_since(SystemTime::UNIX_EPOCH)
    .expect("Duration since UNIX_EPOCH failed");
let mut rng = StdRng::seed_from_u64(d.as_secs());
71
Basic implementation of the Echo program: Print all arguments except the program name, separated by space, followed by newline.
The idiom demonstrates how to skip the first argument if necessary, concatenate arguments as strings, append newline and print it to stdout.
func main() {
    fmt.Println(strings.Join(os.Args[1:], " "))
}
println!("{}", env::args().skip(1).collect::<Vec<_>>().join(" "));
Alternative implementation:
println!("{}", std::env::args().skip(1).format(" "));
73
Create a factory named fact for any sub class of Parent and taking exactly one string str as constructor parameter.
type ParentFactory func(string) Parent

var fact ParentFactory = func(str string) Parent {
	return Parent{
		name: str,
	}
}
fn fact<Parent: std::str::FromStr>(str: String, _: Parent) -> Parent where <Parent as FromStr>::Err: Debug 
{
    return str.parse::<Parent>().unwrap();
}
74
Compute the greatest common divisor x of big integers a and b. Use an integer type able to handle huge numbers.
x.GCD(nil, nil, a, b)
let x = a.gcd(&b);
75
Compute the least common multiple x of big integers a and b. Use an integer type able to handle huge numbers.
gcd.GCD(nil, nil, a, b)
x.Div(a, gcd).Mul(x, b)
let x = a.lcm(&b);
76
Create the string s of integer x written in base 2.

E.g. 13 -> "1101"
s := strconv.FormatInt(x, 2)
Alternative implementation:
s := fmt.Sprintf("%b", x)
let s = format!("{:b}", x);
Alternative implementation:
let s = format!("{x:b}");
77
Declare a complex x and initialize it with value (3i - 2). Then multiply it by i.
x := 3i - 2
x *= 1i
let mut x = Complex::new(-2, 3);
x *= Complex::i();
78
Execute a block once, then execute it again as long as boolean condition c is true.
for{
   someThing()
   someOtherThing()
   if !c {
     break
   }
}
Alternative implementation:
for done := false; !done; {
	someThing()
	someOtherThing()
	done = !c()
}
loop {
    doStuff();
    if !c { break; }
}
Alternative implementation:
while {
   doStuff();
   c
} { /* EMPTY */ }
79
Declare the floating point number y and initialize it with the value of the integer x .
y := float64(x)
let y = x as f64;
80
Declare integer y and initialize it with the value of floating point number x . Ignore non-integer digits of x .
Make sure to truncate towards zero: a negative x must yield the closest greater integer (not lesser).
y := int(x)
let y = x as i32;
81
Declare the integer y and initialize it with the rounded value of the floating point number x .
Ties (when the fractional part of x is exactly .5) must be rounded up (to positive infinity).
y := int(math.Floor(x + 0.5))
let y = x.round() as i64;
82
Find how many times string s contains substring t.
Specify if overlapping occurrences are counted.
x := strings.Count(s, t)
let c = s.matches(t).count();
83
Declare regular expression r matching the strings "http", "htttp", "httttp", etc.
r := regexp.MustCompile("htt+p")
let r = Regex::new(r"htt+p").unwrap();
84
Count number c of 1s in the integer i in base 2.

E.g. i=6 → c=2
func PopCountUInt64(i uint64) (c int) {
	i -= (i >> 1) & 0x5555555555555555
	i = (i>>2)&0x3333333333333333 + i&0x3333333333333333
	i += i >> 4
	i &= 0x0f0f0f0f0f0f0f0f
	i *= 0x0101010101010101
	return int(i >> 56)
}

func PopCountUInt32(i uint32) (n int) {
	i -= (i >> 1) & 0x55555555
	i = (i>>2)&0x33333333 + i&0x33333333
	i += i >> 4
	i &= 0x0f0f0f0f
	i *= 0x01010101
	return int(i >> 24)
}
Alternative implementation:
c := bits.OnesCount(i)
let c = i.count_ones();
85
Write boolean function addingWillOverflow which takes two integers x, y and return true if (x+y) overflows.

An overflow may be above the max positive value, or below the min negative value.
func addingWillOverflow(x int, y int) bool {
	if x > 0 {
		return y > math.MaxInt-x
	}
	return y < math.MinInt-x
}
fn adding_will_overflow(x: usize, y: usize) -> bool {
    x.checked_add(y).is_none()
}
86
Write the boolean function multiplyWillOverflow which takes two integers x, y and returns true if (x*y) overflows.

An overflow may reach above the max positive value, or below the min negative value.
func multiplyWillOverflow(x, y uint64) bool {
   if x <= 1 || y <= 1 {
     return false
   }
   d := x * y
   return d/y != x
}
fn multiply_will_overflow(x: i64, y: i64) -> bool {
    x.checked_mul(y).is_none()
}
87
Exit immediately.
If some extra cleanup work is executed by the program runtime (not by the OS itself), describe it.
os.Exit(0)
std::process::exit(0);
88
Create a new bytes buffer buf of size 1,000,000.
buf := make([]byte, 1_000_000)
let buf: Vec<u8> = Vec::with_capacity(1000000);
89
You've detected that the integer value of argument x passed to the current function is invalid. Write the idiomatic way to abort the function execution and signal the problem.
return nil, fmt.Errorf("invalid value for x: %v", x)
enum CustomError { InvalidAnswer }

fn do_stuff(x: i32) -> Result<i32, CustomError> {
    if x != 42 {
        Err(CustomError::InvalidAnswer)
    } else {
        Ok(x)
    }
}
90
Expose a read-only integer x to the outside world while being writable inside a structure or a class Foo.
type Foo struct {
	x int
}

func (f *Foo) X() int {
	return f.x
}
struct Foo {
    x: usize
}

impl Foo {
    pub fn new(x: usize) -> Self {
        Foo { x }
    }

    pub fn x<'a>(&'a self) -> &'a usize {
        &self.x
    }

    pub fn bar(&mut self) {
        self.x += 1;
    }
}
91
Read from the file data.json and write its content into the object x.
Assume the JSON data is suitable for the type of x.
buffer, err := os.ReadFile("data.json")
if err != nil {
	return err
}
err = json.Unmarshal(buffer, &x)
if err != nil {
	return err
}
Alternative implementation:
r, err := os.Open(filename)
if err != nil {
	return err
}
decoder := json.NewDecoder(r)
err = decoder.Decode(&x)
if err != nil {
	return err
}
let x = ::serde_json::from_reader(File::open("data.json")?)?;
92
Write the contents of the object x into the file data.json.
buffer, err := json.MarshalIndent(x, "", "  ")
if err != nil {
	return err
}
err = os.WriteFile("data.json", buffer, 0644)
::serde_json::to_writer(&File::create("data.json")?, &x)?
93
Implement the procedure control which receives one parameter f, and runs f.
func control(f func()) {
	f()
}
fn control(f: impl Fn()) {
    f();
}
94
Print the name of the type of x. Explain if it is a static type or dynamic type.

This may not make sense in all languages.
fmt.Println(reflect.TypeOf(x))
Alternative implementation:
fmt.Printf("%T", x)
fn type_of<T>(_: &T) -> &'static str {
    std::intrinsics::type_name::<T>()
}

println!("{}", type_of(&x));
95
Assign to variable x the length (number of bytes) of the local file at path.
info, err := os.Stat(path)
if err != nil {
	return err
}
x := info.Size()
let x = fs::metadata(path)?.len();
Alternative implementation:
let x = path.metadata()?.len();
Alternative implementation:
let x = fs::metadata(path)?.st_size();
96
Set the boolean b to true if string s starts with prefix prefix, false otherwise.
b := strings.HasPrefix(s, prefix)
let b = s.starts_with(prefix);
97
Set boolean b to true if string s ends with string suffix, false otherwise.
b := strings.HasSuffix(s, suffix)
let b = s.ends_with(suffix);
98
Convert a timestamp ts (number of seconds in epoch-time) to a date with time d. E.g. 0 -> 1970-01-01 00:00:00
d := time.Unix(ts, 0)
let d = NaiveDateTime::from_timestamp(ts, 0);
99
Assign to the string x the value of the fields (year, month, day) of the date d, in format YYYY-MM-DD.
x := d.Format("2006-01-02")
Utc::today().format("%Y-%m-%d")
Alternative implementation:
let format = format_description!("[year]-[month]-[day]");
let x = d.format(&format).expect("Failed to format the date");
100
Sort elements of array-like collection items, using a comparator c.
type ItemCSorter []Item
func (s ItemCSorter) Len() int           { return len(s) }
func (s ItemCSorter) Less(i, j int) bool { return c(s[i], s[j]) }
func (s ItemCSorter) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }

func sortItems(items []Item) {
	sorter := ItemCSorter(items)
	sort.Sort(sorter)
}
Alternative implementation:
type ItemsSorter struct {
	items []Item
	c     func(x, y Item) bool
}

func (s ItemsSorter) Len() int           { return len(s.items) }
func (s ItemsSorter) Less(i, j int) bool { return s.c(s.items[i], s.items[j]) }
func (s ItemsSorter) Swap(i, j int)      { s.items[i], s.items[j] = s.items[j], s.items[i] }

func sortItems(items []Item, c func(x, y Item) bool) {
	sorter := ItemsSorter{
		items,
		c,
	}
	sort.Sort(sorter)
}
Alternative implementation:
sort.Slice(items, func(i, j int) bool {
	return c(items[i], items[j])
})
Alternative implementation:
slices.SortFunc(items, c)
items.sort_by(c);
101
Make an HTTP request with method GET to the URL u, then store the body of the response in the string s.
res, err := http.Get(u)
if err != nil {
	return err
}
buffer, err := io.ReadAll(res.Body)
res.Body.Close()
if err != nil {
	return err
}
s := string(buffer)
let client = Client::new();
let s = client.get(u).send().and_then(|res| res.text())?;
Alternative implementation:
let s = ureq::get(u).call().into_string()?;
Alternative implementation:
let mut response = reqwest::blocking::get(u)?;
let mut s = String::new();
response.read_to_string(&mut s)?;
102
Make an HTTP request with method GET to the URL u, then store the body of the response in the file result.txt. Try to save the data as it arrives if possible, without having all its content in memory at once.
out, err := os.Create("result.txt")
if err != nil {
	return err
}
defer out.Close()

resp, err := http.Get(u)
if err != nil {
	return err
}
defer func() {
	io.Copy(io.Discard, resp.Body)
	resp.Body.Close()
}()
if resp.StatusCode != 200 {
	return fmt.Errorf("Status: %v", resp.Status)
}

_, err = io.Copy(out, resp.Body)
if err != nil {
	return err
}
let client = Client::new();
match client.get(&u).send() {
    Ok(res) => {
        let file = File::create("result.txt")?;
        ::std::io::copy(res, file)?;
    },
    Err(e) => eprintln!("failed to send request: {}", e),
};
103
Read from the file data.xml and write its contents into the object x.
Assume the XML data is suitable for the type of x.
buffer, err := os.ReadFile("data.xml")
if err != nil {
	return err
}
err = xml.Unmarshal(buffer, &x)
if err != nil {
	return err
}
104
Write the contents of the object x into the file data.xml.
buffer, err := xml.MarshalIndent(x, "", "  ")
if err != nil {
	return err
}
err = os.WriteFile("data.xml", buffer, 0644)
105
Assign to the string s the name of the currently executing program (but not its full path).
path := os.Args[0]
s = filepath.Base(path)
Alternative implementation:
path, err := os.Executable()
if err != nil {
  panic(err)
}
s = filepath.Base(path)
fn get_exec_name() -> Option<String> {
    std::env::current_exe()
        .ok()
        .and_then(|pb| pb.file_name().map(|s| s.to_os_string()))
        .and_then(|s| s.into_string().ok())
}

fn main() -> () {
    let s = get_exec_name().unwrap();
    println!("{}", s);
}
Alternative implementation:
let s = std::env::current_exe()
    .expect("Can't get the exec path")
    .file_name()
    .expect("Can't get the exec name")
    .to_string_lossy()
    .into_owned();
106
Assign to string dir the path of the working directory.
(This is not necessarily the folder containing the executable itself)
dir, err := os.Getwd()
let dir = env::current_dir().unwrap();
107
Assign to string dir the path of the folder containing the currently running executable.
(This is not necessarily the working directory, though.)
programPath := os.Args[0]
absolutePath, err := filepath.Abs(programPath)
if err != nil {
	return err
}
dir := filepath.Dir(absolutePath)
let dir = std::env::current_exe()?
    .canonicalize()
    .expect("the current exe should exist")
    .parent()
    .expect("the current exe should be a file")
    .to_string_lossy()
    .to_owned();
109
Set n to the number of bytes of a variable t (of type T).
var t T
tType := reflect.TypeOf(t)
n := tType.Size()
let n = std::mem::size_of::<T>();
110
Set the boolean blank to true if the string s is empty, or null, or contains only whitespace ; false otherwise.
blank := strings.TrimSpace(s) == ""
let blank = s.trim().is_empty();
Alternative implementation:
let blank = s.chars().all(|c| c.is_whitespace());
111
From current process, run program x with command-line parameters "a", "b".
err := exec.Command("x", "a", "b").Run()
let output = Command::new("x")
    .args(&["a", "b"])
    .spawn()
    .expect("failed to execute process");
Alternative implementation:
let output = Command::new("x")
        .args(&["a", "b"])
        .output()
        .expect("failed to execute process");
Alternative implementation:
let output = Command::new("x")
        .args(&["a", "b"])
        .status()
        .expect("failed to execute process");
112
Print each key k with its value x from an associative array mymap, in ascending order of k.
keys := make([]string, 0, len(mymap))
for k := range mymap {
	keys = append(keys, k)
}
sort.Strings(keys)

for _, k := range keys {
	x := mymap[k]
	fmt.Println("Key =", k, ", Value =", x)
}
Alternative implementation:
keys := maps.Keys(mymap)
slices.Sort(keys)

for _, k := range keys {
	x := mymap[k]
	fmt.Println("Key =", k, ", Value =", x)
}
Alternative implementation:
keys := maps.Keys(mymap)
slices.SortFunc(keys, compare)

for _, k := range keys {
	x := mymap[k]
	fmt.Println("Key =", k, ", Value =", x)
}
for (k, x) in mymap {
    println!("({}, {})", k, x);
}
113
Print each key k with its value x from an associative array mymap, in ascending order of x.
Multiple entries may exist for the same value x.
type entry struct {
	key   string
	value int
}

type entries []entry
func (list entries) Len() int { return len(list) }
func (list entries) Less(i, j int) bool { return list[i].value < list[j].value }
func (list entries) Swap(i, j int) { list[i], list[j] = list[j], list[i] }

entries := make(entries, 0, len(mymap))
for k, x := range mymap {
	entries = append(entries, entry{key: k, values: x})
}
sort.Sort(entries)

for _, e := range entries {
	fmt.Println("Key =", e.key, ", Value =", e.value)
}
Alternative implementation:
type entry struct {
	key   string
	value int
}

entries := make([]entry, 0, len(mymap))
for k, x := range mymap {
	entries = append(entries, entry{key: k, value: x})
}
sort.Slice(entries, func(i, j int) bool {
	return entries[i].value < entries[j].value
})

for _, e := range entries {
	fmt.Println("Key =", e.key, ", Value =", e.value)
}
for (k, x) in mymap.iter().sorted_by_key(|x| x.1) {
	println!("[{},{}]", k, x);
}
Alternative implementation:
let mut items: Vec<_> = mymap.iter().collect();
items.sort_by_key(|item| item.1);
for (k, x) in items {
    println!("[{},{}]", k, x);
}
114
Set boolean b to true if objects x and y contain the same values, recursively comparing all referenced elements in x and y.
Tell if the code correctly handles recursive types.
b := reflect.DeepEqual(x, y)
let b = x == y;
115
Set boolean b to true if date d1 is strictly before date d2 ; false otherwise.
b := d1.Before(d2)
let b = d1 < d2;
116
Remove all occurrences of string w from string s1, and store the result in s2.
s2 := strings.Replace(s1, w, "", -1)
Alternative implementation:
s2 := strings.ReplaceAll(s1, w, "")
s2 = s1.replace(w, "");
Alternative implementation:
let s2 = str::replace(s1, w, "");
117
Set n to the number of elements of the list x.
n := len(x)
let n = x.len();

118
Create the set y from the list x.
x may contain duplicates. y is unordered and has no repeated values.
y := make(map[T]struct{}, len(x))
for _, v := range x {
	y[v] = struct{}{}
}
Alternative implementation:
func sliceToSet[T comparable](x []T) map[T]struct{} {
	y := make(map[T]struct{}, len(x))
	for _, v := range x {
		y[v] = struct{}{}
	}
	return y
}
let y: HashSet<_> = x.into_iter().collect();
119
Remove duplicates from the list x.
Explain if the original order is preserved.
y := make(map[T]struct{}, len(x))
for _, v := range x {
	y[v] = struct{}{}
}
x2 := make([]T, 0, len(y))
for _, v := range x {
	if _, ok := y[v]; ok {
		x2 = append(x2, v)
		delete(y, v)
	}
}
x = x2
Alternative implementation:
seen := make(map[T]bool)
j := 0
for _, v := range x {
	if !seen[v] {
		x[j] = v
		j++
		seen[v] = true
	}
}
x = x[:j]
Alternative implementation:
seen := make(map[T]bool)
j := 0
for _, v := range x {
	if !seen[v] {
		x[j] = v
		j++
		seen[v] = true
	}
}
for i := j; i < len(x); i++ {
	x[i] = nil
}
x = x[:j]
Alternative implementation:
func deduplicate[S ~[]T, T comparable](x S) S {
	seen := make(map[T]bool)
	j := 0
	for _, v := range x {
		if !seen[v] {
			x[j] = v
			j++
			seen[v] = true
		}
	}
	var zero T
	for i := j; i < len(x); i++ {
		// Avoid memory leak
		x[i] = zero
	}
	return x[:j]
}
Alternative implementation:
slices.Sort(x)
x = slices.Compact(x)
x.sort();
x.dedup();
Alternative implementation:
let dedup: Vec<_> = x.iter().unique().collect();
120
Read an integer value from the standard input into the variable n
_, err := fmt.Scan(&n)
Alternative implementation:
_, err := fmt.Scanf("%d", &n)
fn get_input() -> String {
    let mut buffer = String::new();
    std::io::stdin().read_line(&mut buffer).expect("Failed");
    buffer
}

let n = get_input().trim().parse::<i64>().unwrap();
Alternative implementation:
let mut input = String::new();
io::stdin().read_line(&mut input).unwrap();
let n: i32 = input.trim().parse().unwrap();
Alternative implementation:
let n: i32 = std::io::stdin()
    .lock()
    .lines()
    .next()
    .expect("stdin should be available")
    .expect("couldn't read from stdin")
    .trim()
    .parse()
    .expect("input was not an integer");
Alternative implementation:
let n: i32 = read!();
121
Listen UDP traffic on port p and read 1024 bytes into the buffer b.
ServerAddr,err := net.ResolveUDPAddr("udp",p)
if err != nil {
	return err
}
ServerConn, err := net.ListenUDP("udp", ServerAddr)
if err != nil {
	return err
}
defer ServerConn.Close()
n,addr,err := ServerConn.ReadFromUDP(b[:1024])
if err != nil {
	return err
}
if n<1024 {
	return fmt.Errorf("Only %d bytes could be read.", n)
}
let mut b = [0 as u8; 1024];
let sock = UdpSocket::bind(("localhost", p)).unwrap();
sock.recv_from(&mut b).unwrap();
122
Create an enumerated type Suit with 4 possible values SPADES, HEARTS, DIAMONDS, CLUBS.
type Suit int

const (
  Spades Suit = iota
  Hearts
  Diamonds
  Clubs
)
enum Suit {
    Spades,
    Hearts,
    Diamonds,
    Clubs,
}
123
Verify that predicate isConsistent returns true, otherwise report assertion violation.
Explain if the assertion is executed even in production environment or not.
if !isConsistent() {
	panic("State consistency violated")
}
assert!(is_consistent);
124
Write the function binarySearch which returns the index of an element having the value x in the sorted array a, or -1 if no such element exists.
func binarySearch(a []T, x T) int {
	imin, imax := 0, len(a)-1
	for imin <= imax {
		imid := imin + (imax-imin) / 2
		switch {
		case a[imid] == x:
			return imid
		case a[imid] < x:
			imin = imid + 1
		default:
			imax = imid - 1
		}
	}
	return -1
}
Alternative implementation:
func binarySearch(a []int, x int) int {
	i := sort.SearchInts(a, x)
	if i < len(a) && a[i] == x {
		return i
	}
	return -1
}
Alternative implementation:
func binarySearch(a []T, x T) int {
	f := func(i int) bool { return a[i] >= x }
	i := sort.Search(len(a), f)
	if i < len(a) && a[i] == x {
		return i
	}
	return -1
}
Alternative implementation:
func binarySearch(a []T, x T) int {
	if i, ok := slices.BinarySearch(a, x); ok {
		return i
	} else {
		return -1
	}
}
a.binary_search(&x).unwrap_or(-1);
125
measure the duration t, in nanoseconds, of a call to the function foo. Print this duration.
t1 := time.Now()
foo()
t := time.Since(t1)
ns := int64(t / time.Nanosecond)
fmt.Printf("%dns\n", ns)
Alternative implementation:
t1 := time.Now()
foo()
t := time.Since(t1)
ns := t.Nanoseconds()
fmt.Printf("%dns\n", ns)
let start = Instant::now();
foo();
let duration = start.elapsed();
println!("{}", duration);
126
Write a function foo that returns a string and a boolean value.
func foo() (string, bool) {
	return "Too good to be", true
}
fn foo() -> (String, bool) {
    (String::from("bar"), true)
}
127
Import the source code for the function foo body from a file "foobody.txt".
//go:embed foobody.txt
var s string

fn main() {
    include!("foobody.txt");
}
128
Call a function f on every node of a tree, in breadth-first prefix order
func (root *Tree) Bfs(f func(*Tree)) {
	if root == nil {
		return
	}
	queue := []*Tree{root}
	for len(queue) > 0 {
		t := queue[0]
		queue = queue[1:]
		f(t)
		queue = append(queue, t.Children...)
	}
}
struct Tree<V> {
    children: Vec<Tree<V>>,
    value: V
}

impl<V> Tree<V> {
    fn bfs(&self, f: impl Fn(&V)) {
        let mut q = VecDeque::new();
        q.push_back(self);

        while let Some(t) = q.pop_front() {
            (f)(&t.value);
            for child in &t.children {
                q.push_back(child);
            }
        }
    }
}
129
Call the function f on every vertex accessible from the vertex start, in breadth-first prefix order
func (start *Vertex) Bfs(f func(*Vertex)) {
	queue := []*Vertex{start}
	seen := map[*Vertex]bool{start: true}
	for len(queue) > 0 {
		v := queue[0]
		queue = queue[1:]
		f(v)
		for next, isEdge := range v.Neighbours {
			if isEdge && !seen[next] {
				queue = append(queue, next)
				seen[next] = true
			}
		}
	}
}
struct Vertex<V> {
	value: V,
	neighbours: Vec<Weak<RefCell<Vertex<V>>>>,
}

// ...

fn bft(start: Rc<RefCell<Vertex<V>>>, f: impl Fn(&V)) {
	let mut q = vec![start];
	let mut i = 0;
	while i < q.len() {
	    let v = Rc::clone(&q[i]);
	    i += 1;
	    (f)(&v.borrow().value);
	    for n in &v.borrow().neighbours {
	        let n = n.upgrade().expect("Invalid neighbour");
	        if q.iter().all(|v| v.as_ptr() != n.as_ptr()) {
	            q.push(n);
	        }
	    }
	}
}
130
Call th function f on every vertex accessible from the vertex v, in depth-first prefix order
func (v *Vertex) Dfs(f func(*Vertex), seen map[*Vertex]bool) {
	seen[v] = true
	f(v)
	for next, isEdge := range v.Neighbours {
		if isEdge && !seen[next] {
			next.Dfs(f, seen)
		}
	}
}
Alternative implementation:
func (v *Vertex[L]) Dfs(f func(*Vertex[L]), seen map[*Vertex[L]]bool) {
	seen[v] = true
	f(v)
	for next, isEdge := range v.Neighbours {
		if isEdge && !seen[next] {
			next.Dfs(f, seen)
		}
	}
}
struct Vertex<V> {
	value: V,
	neighbours: Vec<Weak<RefCell<Vertex<V>>>>,
}

// ...

fn dft_helper(start: Rc<RefCell<Vertex<V>>>, f: &impl Fn(&V), s: &mut Vec<*const Vertex<V>>) {
	s.push(start.as_ptr());
	(f)(&start.borrow().value);
	for n in &start.borrow().neighbours {
		let n = n.upgrade().expect("Invalid neighbor");
		if s.iter().all(|&p| p != n.as_ptr()) {
			Self::dft_helper(n, f, s);
		}
	}
}
131
Execute f1 if condition c1 is true, or else f2 if condition c2 is true, or else f3 if condition c3 is true.
Don't evaluate a condition when a previous condition was true.
switch {
case c1:
	f1()
case c2:
	f2()
case c3:
	f3()
}
if c1 { f1() } else if c2 { f2() } else if c3 { f3() }
Alternative implementation:
match true {
    _ if c1 => f1(),
    _ if c2 => f2(),
    _ if c3 => f3(),
    _ => (),
}
132
Run the procedure f, and return the duration of the execution of f.
func clock(f func()) time.Duration {
	t := time.Now()
	f()
	return time.Since(t)
}
let start = Instant::now();
f();
let duration = start.elapsed();
133
Set boolean ok to true if string word is contained in string s as a substring, even if the case doesn't match, or to false otherwise.
lowerS, lowerWord := strings.ToLower(s), strings.ToLower(word)
ok := strings.Contains(lowerS, lowerWord)
let re = Regex::new(&format!("(?i){}", regex::escape(word))).unwrap();
let ok = re.is_match(&s);
Alternative implementation:
let re =
    RegexBuilder::new(&regex::escape(word))
    .case_insensitive(true)
    .build().unwrap();

let ok = re.is_match(s);
Alternative implementation:
let ok = s.to_ascii_lowercase().contains(&word.to_ascii_lowercase());
134
Declare and initialize a new list items, containing 3 elements a, b, c.
items := []T{a, b, c}
let items = vec![a, b, c];
135
Remove at most 1 item from list items, having the value x.
This will alter the original list or return a new list, depending on which is more idiomatic.
If there are several occurrences of x in items, remove only one of them. If x is absent, keep items unchanged.
for i, y := range items {
	if y == x {
		items = append(items[:i], items[i+1:]...)
		break
	}
}
Alternative implementation:
for i, y := range items {
	if y == x {
		copy(items[i:], items[i+1:])
		items[len(items)-1] = nil
		items = items[:len(items)-1]
		break
	}
}
Alternative implementation:
func removeFirstByValue[S ~[]T, T comparable](items *S, x T) {
	for i, y := range *items {
		if y == x {
			*items = slices.Delete(*items, i, i+1)
			return
		}
	}
}
Alternative implementation:
func removeFirstByValue[S ~[]T, T comparable](items *S, x T) {
	if i := slices.Index(*items, x); i != -1 {
		*items = slices.Delete(*items, i, i+1)
	}
}
if let Some(i) = items.iter().position(|item| *item == x) {
    items.remove(i);
}
136
Remove all occurrences of the value x from list items.
This will alter the original list or return a new list, depending on which is more idiomatic.
items2 := make([]T, 0, len(items))
for _, v := range items {
	if v != x {
		items2 = append(items2, v)
	}
}
Alternative implementation:
j := 0
for i, v := range items {
	if v != x {
		items[j] = items[i]
		j++
	}
}
items = items[:j]
Alternative implementation:
j := 0
for i, v := range items {
	if v != x {
		items[j] = items[i]
		j++
	}
}
for k := j; k < len(items); k++ {
	items[k] = nil
}
items = items[:j]
Alternative implementation:
func removeAll[S ~[]T, T comparable](items *S, x T) {
	j := 0
	for i, v := range *items {
		if v != x {
			(*items)[j] = (*items)[i]
			j++
		}
	}
	var zero T
	for k := j; k < len(*items); k++ {
		(*items)[k] = zero
	}
	*items = (*items)[:j]
}
Alternative implementation:
items = slices.DeleteFunc(items, func(e T) bool {
	return e == x
})
items = items.into_iter().filter(|&item| item != x).collect();
Alternative implementation:
items.retain(|&item| item != x);
137
Set the boolean b to true if the string s contains only characters in the range '0'..'9', false otherwise.
b := true
for _, c := range s {
	if c < '0' || c > '9' {
		b = false
		break
	}
}
Alternative implementation:
isNotDigit := func(c rune) bool { return c < '0' || c > '9' }
b := strings.ContainsFunc(s, isNotDigit) 
let chars_are_numeric: Vec<bool> = s.chars()
				.map(|c|c.is_numeric())
				.collect();
let b = !chars_are_numeric.contains(&false);
Alternative implementation:
let b = s.chars().all(char::is_numeric);
Alternative implementation:
let b = s.bytes().all(|c| c.is_ascii_digit());
138
Create a new temporary file on the filesystem.
tmpfile, err := os.CreateTemp("", "")
let temp_dir = TempDir::new("prefix")?;
let temp_file = File::open(temp_dir.path().join("file_name"))?;
139
Create a new temporary folder on filesystem, for writing.
dir, err := os.MkdirTemp("", "")
let tmp = TempDir::new("prefix")?;
140
Delete from map m the entry having key k.

Explain what happens if k is not an existing key in m.
delete(m, k)
m.remove(&k);
141
Iterate in sequence over the elements of the list items1 then items2. For each iteration print the element.
for _, v := range items1 {
	fmt.Println(v)
}
for _, v := range items2 {
	fmt.Println(v)
}
for i in item1.iter().chain(item2.iter()) {
    print!("{} ", i);
}
142
Assign to string s the hexadecimal representation (base 16) of integer x.

E.g. 999 -> "3e7"
s := strconv.FormatInt(x, 16)