Creating implementation for idiom 7 : Iterate over list indexes and values

Idiom

# 7 Iterate over list indexes and values

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Lead paragraph

Print each index i with its value x from an array-like collection items

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Other implementations

with Ada.Text_IO;
use Ada.Text_IO;

for I in Items'Range loop
   X := Items (I);
   Put_Line (Integer'Image (I) & " " & Integer'Image (X));
end loop;

for (size_t i = 0; i < n; i++) {
  printf("Item %d = %s\n", i, toString(items[i]));
}

(* output_elem is a printer for elements of [items] *)
items |> List.iteri (fun i x ->
	printf "%d: %a" i output_elem x
)

(doseq [[i x] (map-indexed vector items)]
  (println i ":" x))

#include <cstdio>

for (int i {}; auto& x : items)
    printf("%d, %s\n", i++, x);

#include <iostream>

std::size_t i = 0;
for(const auto & x: items) {
  std::cout << "Item " << i++ << " = " << x << std::endl;
}

#include <ranges>

for (auto const [i, x] : std::views::enumerate(items)) {
  std::cout << i << ": " << x << '\n';
}

#include <iostream>

for (std::size_t ix = 0; ix < items.size(); ++ix) {
  std::cout << "Item " << ix << " = " << items[ix] << std::endl;
}

using System.Collections.Generic;

foreach (var (i, x) in items.AsIndexed())
{
    System.Console.WriteLine($"{i}: {x}");
}

public static class Extensions
{
    public static IEnumerable<(int, T)> AsIndexed<T>(
        this IEnumerable<T> source)
    {
        var index = 0;
        foreach (var item in source)
        {
            yield return (index++, item);
        }
    }
}

Demo

using System;

for (int i = 0; i < items.Length; i++)
{
    Console.WriteLine($"{i} {items[i]}");
}

using System.Linq;

foreach (var (x, i) in items.Select((x, i)=>(x, i)))
{
    System.Console.WriteLine($"{i}: {x}");
}

import std.stdio;

foreach(i, x; items)
{
   writefln("%s: %s", i, x);
}

import std.stdio, std.algorithm;
import std.range;

items.enumerate.each!(a => writeln("i = ", a[0], " value = ", a[1]));

Demo
Doc

import 'package:collection/collection.dart';

items.forEachIndexed((i, x) {
  print('index=$i, value=$x');
});

for (var i = 0; i < items.length; i++) {
  print('index=$i, value=${items[i]}');
}

Demo

items.asMap().forEach((i, x) {
  print('index=$i, value=$x');
});

Demo
Doc

items
|> Enum.with_index
|> Enum.each(fn({x, i}) ->
  IO.puts("#{i} => #{x}")
end)

Demo
Doc

WithIndex =
  lists:zip(lists:seq(1, length(Items)), Items),
io:format("~p~n", [WithIndex]).

Demo
Doc

do i=1, size(items)
  print *,i, items(i)
end do

import "fmt"

for i, x := range items {
    fmt.Printf("Item %d = %v \n", i, x)
}

Demo
Doc

items.eachWithIndex {
  x, i -> println "Item $i = $x"
}

Demo

mapM_ print (zip [0..] items)

for (var i in items) {
   console.log("index=" + i + ", value=" + items[i]);
}

items.forEach((val, idx) => {
  console.log("index=" + idx + ", value=" + val);
});

import static java.lang.System.out;

int i, n;
for (i = 0, n = items.size(); i < n; ++i)
    out.println(i + " = " + items.get(i));

import static java.lang.System.out;

int i, n;
for (i = 0, n = items.length; i < n; ++i)
    out.println(i + " = " + items[i]);

import static java.lang.System.out;

int i = 0;
for (T t : items)
    out.println(i++ + " = " + t);

import static java.lang.System.out;
import static java.util.stream.IntStream.range;

range(0, items.length)
    .forEach(i -> {
        out.println(i + " = " + items[i]);
    });

items.forEachIndexed { i, x -> 
  println("i=$i x=$x") 
}

Demo

(loop for i from 0 and x across items
      do (format t "~a = ~a~%" i x))

for i, x in ipairs(items) do
	print('Index: '..i..', Value: '..x)
end

@import Foundation;

[items enumerateObjectsUsingBlock:^(id x, NSUInteger i, BOOL *stop) {
  NSLog(@"Item %lu = %@",(u_long)i,x);
}];

foreach ($items as $i=>$x)
{
    echo "i=$i, x=$x"; echo '<br>';
}

var I:Integer;
    Items: array of String;
[..]
  for I := 0 to high(Items) do
    WriteLn('Item ', I, ' = ', Items[I]);

uses Classes, SysUtils;

var I:Integer;
    Items: array of TObject;
[...]
  for I := 0 to high(Items) do
    if assigned(Items[I]) then
      WriteLn(Format('Item %d = %s', [I, Items[I].ToString]));

use 5.012; # each @array

while (my ($i, $x) = each @items) {
    print "array[$i] = $x\n";
}

for i, x in enumerate(items):
    print(i, x)

Doc
Origin

i = 0
for x in items:
    print(i, x)
    i += 1

i = 0
length = len(items)
while i != length:
    x = items[i]
    print(i, x)
    i += 1

items.each_with_index do |x, i| 
  puts "Item #{i} = #{x}"
end

Demo
Doc

items.each_index{|i| puts "Item %d = %s" % [i, items[i]]}

Demo
Doc

for (i, x) in items.iter().enumerate() {
    println!("Item {} = {}", i, x);
}

Demo
Doc

items.iter().enumerate().for_each(|(i, x)| {
    println!("Item {} = {}", i, x);
})

Demo
Doc

val items = List("a", "b", "c")
items.zipWithIndex.foreach{ case (item, index) => 
  println(s"$index => $item")
}

(define (display-list items)
  (define (display-list items i)
    (if (not (null? items))
        (begin
          (display (string-append
                    (number->string i)
                    ": "
                    (number->string (first items))
                    "\n"))
          (display-list (rest items) (+ i 1)))
        'done))
  (display-list items 0))

items withIndexDo: [:item :index |
  Transcript showln: 'item: ' , item asString , ' index: ' , index asString].

Imports System

For i As Integer = 0 To items.Count - 1
    Dim x = items(i)
    Console.WriteLine($"Item {i} = {x}")
Next

Demo

For i = LBound(items) To UBound(items)
    x = items(i)
    Debug.Print i & ": " & x
Next

Imports System

For i As Integer = 0 To items.Length - 1
    Dim x = items(i)
    Console.WriteLine($"Item {i} = {x}")
Next

Demo

Preview