Creating an Array

Creating an Array
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This task is about numeric arrays. For hashes or associative arrays, please see Creating an Associative Array.

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In this task, the goal is to create an array.

Ada

Compiler: GCC 4.1.2

type Arr is array (Positive range <>) of Integer;
Uninitialized : Arr (1 .. 10);
Initialized_1 : Arr (1 .. 20) := (others => 1);
Initialized_2 : Arr := (1 .. 30 => 2);
Const         : constant Arr := (1 .. 10 => 1, 11 .. 20 => 2, 21 | 22 => 3);

BASIC

Interpeter: QuickBasic 4.5, PB 7.1

' $DYNAMIC
DIM SHARED myArray(-10 TO 10, 10 TO 30) AS STRING
REDIM SHARED myArray(20, 20) AS STRING
myArray(1,1) = "Item1"
myArray(1,2) = "Item2"

C

Compiler: GCC, MSVC, BCC, Watcom

Libraries: None are needed

 // Dynamic
 int n = 10 * sizeof(int);
 int *myArray = (int*)malloc(n);
 if(myArray != NULL)
 {
   memset(myArray, 0, n);
   myArray[0] = 1;
   myArray[1] = 2;
   free(myArray);
   myArray = NULL;
 }

Libraries: None are needed

 // Static
 int myArray2[10] = { 1, 2, 0}; /* 3..9 := 0 */

C++

Compiler: GCC, Visual C++, BCC, Watcom

 // Dynamic
 const int n = 10;
 int* myArray = new int[n];
 if(myArray != NULL)
 {
   myArray[0] = 1;
   myArray[1] = 2;
   delete[] myArray;
   myArray = NULL;
 }

 // Static
 int myArray2[10] = { 1, 2, 0}; /* 3..9 := 0 */

Libraries: STL

 // STL
 std::vector<int> myArray3(10);
 myArray3.push_back(1);
 myArray3.push_back(2);

Libraries: Qt

 // Qt
 QVector<int> myArray4(10);
 myArray4.push_back(1);
 myArray4.push_back(2);

Libraries: Microsoft Foundation Classes

 // MFC
 CArray<int,int> myArray5(10);
 myArray5.Add(1);
 myArray5.Add(2);

C#

Example of array of 10 int types:

 int[] numbers = new int[10];

Example of array of 3 string types:

 string[] words = { "these", "are", "arrays" };

You can also declare the size of the array and initialize the values at the same time:

 int[] more_numbers = new int[3]{ 21, 14 ,63 };

For Multi-Deminsional arrays you delcare them the same except for a comma in the type declaration.

The following creates a 3x2 int matrix

 int[,] number_matrix = new int[3][2];

As with the previous examples you can also initialize the values of the array, the only difference being each row in the matrix must be enclosed in its own braces.

 string[,] string_matrix = { {"I","swam"}, {"in","the"}, {"freezing","water"} };

or

 string[,] funny_matrix = new string[2][2]{ {"clowns", "are"} , {"not", "funny"} };

Perl

Interpeter: Perl

use vars qw{ @Array };

@Array=(
        [0,0,0,0,0,0],
        [1,1,1,1,1,1],
        [2,2,2,2,2,2],
        [3,3,3,3,3,3]
      );
#You would call the array by this code. This will call the 3rd 1 on the second list
print $Array[1][3];

 # Alternative:
 my @array_using_qw = qw/coffee sugar cream/;

 # Alternative:
 my @Array3 = ();
 push @Array3,   "Item1";
 push @Array3,   "Item2";
 $Array3[2]    = "Item3";
 $Array3[3][0] = "Item4";

 @Array = ('This', 'That', 'And', 'The', 'Other');

 $ArrayRef = ['This', 'That', 'And', 'The', 'Other'];
 print $ArrayRef->[2]; # would print "And"

PHP

For a single dimension array with 10 elements:

 $array = array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)    //$array[3] == 3
  
 $array = array("a", "b", "c", "d", "e", "f", "g", "h", "i", "j")    //$array[3] == "c"

For a multi-dimension array:

$array = array(
               array(0, 0, 0, 0, 0, 0),
               array(1, 1, 1, 1, 1, 1),
               array(2, 2, 2, 2, 2, 2),
               array(3, 3, 3, 3, 3, 3)
         );
#You would call the array by this code. This will call the 3rd 1 on the second list
echo $array[1][3];

Python

Interpeter: Python 2.3, 2.4, 2.5 Libraries: None are needed

Array=[
       [0,0,0,0,0,0],
       [1,1,1,1,1,1],
       [2,2,2,2,2,2],
       [3,3,3,3,3,3]
      ]
#You would call the array by this code. This will call the 3rd 1 on the second list
Array[1][3]

Alternatively you can create it programmatically with a list comprehension:

Array = [ [i]*6 for i in range(4) ]

Create an empty array:

Array = []

Ruby

my_array = Array.new
# This is the most basic way to create an empty one-dimensional array in Ruby.

array = [
  [0, 0, 0, 0, 0, 0],
  [1, 1, 1, 1, 1, 1],
  [2, 2, 2, 2, 2, 2],
  [3, 3, 3, 3, 3, 3]
]

# You would call the array by this code. This will call the 3rd 1 on the second list
array[1][3]

# You can also create a sequential array from a range using the 'splat' operator:
array = [*0..3]
# or use the .to_a method for Ranges
array = (0..3).to_a

#=> [0,1,2,3]

# This lets us create the above programmatically:
array = [*0..3].map {|i| [i] * 6}
# or use the .map (.collect which is the same) method for Ranges directly
# note also that arrays of length 6 with a default element are created using Array.new
array = (0..3).map {|i| Array.new(6,i)}

#=> [[0, 0, 0, 0, 0, 0], [1, 1, 1, 1, 1, 1], [2, 2, 2, 2, 2, 2], [3, 3, 3, 3, 3, 3]]

Java

For example for an array of 10 int values:

 int[] intArray = new int[10];

Creating an array of Strings:

 String[] s = {"hello" , "World" };

JavaScript

 var myArray = new Array();
 var myArray2 = new Array("Item1","Item2");
 var myArray3 = ["Item1", "Item2"];

3DS Max 8 - MaxScript

 myArray = #()
 myArray2 = #("Item1", "Item2")

mIRC

Interpeter: mIRC Script Editor Libraries: mArray Snippet

alias creatmearray { .echo -a $array_create(MyArray, 5, 10) }

OCaml

Using an array literal:

 let array = [| 1; 2; 3; 4; 5 |];;

To create an array of five elements with the value 0:

 let num_items = 5 and initial_value = 0;;
 let array = Array.make num_items initial_value

To create an array with contents defined by passing each index to a callback (in this example, the array is set to the squares of the numbers 0 through 4):

 let callback index = index * index;;
 let array = Array.init 5 callback

Smalltalk

  array := Array withAll: #('an' 'apple' 'a' 'day' 'keeps' 'the' 'doctor' 'away').

  "Access the first element of the array"
  elem := array at: 1.

  "Replace apple with orange"
  array at: 2 put: 'orange'.

Visual Basic .Net

Compiler: Visual Studio .NET 2005

Dim myArray() as String = New String() {"Hello", "World", "!"}