Jagged array

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Memory layout of a jagged array.

In computer science, a ragged array, also known as a jagged array, is an array of arrays of which the member arrays can be of different sizes and [1] producing rows of jagged edges when visualized as output. In contrast, two-dimensional arrays are always rectangular[2] so jagged arrays should not be confused with multidimensional arrays, but the former is often used to emulate the latter.

Arrays of arrays in languages such as Java, PHP, Python (multidimensional lists), Ruby, C#.Net, Visual Basic.NET, Perl, JavaScript, Objective-C, Swift, and Atlas Autocode are implemented as Iliffe vectors.

Examples[edit]

In C# and Java[3] jagged arrays can be created with the following code:[4]

int[][]c;
c = new int[2][]; // creates 2 rows
c[0] = new int[5]; // 5 columns for row 0
c[1] = new int[3]; // create 3 columns for row 1

In C and C++, a jagged array can be created using the following code:

int jagged_row0[] = {0,1};
int jagged_row1[] = {1,2,3};
int *jagged[] = { jagged_row0, jagged_row1 };

In C/C++, jagged arrays can also be created with an array of pointers:

int *jagged[5];

jagged[0] = malloc(sizeof(int) * 10);
jagged[1] = malloc(sizeof(int) * 3);

In C++/CLI, jagged array can be created with the code:[5]

using namespace System;
int main()
{
    array<array<double> ^> ^ Arrayname = gcnew array <array<double> ^> (4); // array contains 4 
    //elements
    return 0;
}

In Python, jagged arrays are not native but one can use list comprehensions to create a multi-dimensional list which supports any dimensional matrix:[6]

multi_list_3d = [[[] for i in range(3)] for i in range(3)]
# Produces: [[[], [], []], [[], [], []], [[], [], []]]

multi_list_5d = [[[] for i in range(5)] for i in range(5)]
# Produces: [[[], [], [], [], []], [[], [], [], [], []], [[], [], [], [], []], [[], [], [], [], []], [[], [], [], [], []]]

See also[edit]

References[edit]

  1. ^ Jesse Liberty; Brian MacDonald (18 November 2008). Learning C# 3.0. "O'Reilly Media, Inc.". pp. 210–. ISBN 978-0-596-55420-0.
  2. ^ Don Box (2002). Essential .Net: The Common Language Runtime. Addison-Wesley Professional. p. 138. ISBN 978-0-201-73411-9.
  3. ^ "Jagged Array in Java - GeeksforGeeks". GeeksforGeeks. 2016-02-03. Retrieved 2018-08-13.
  4. ^ Paul J. Deitel; Harvey M. Deitel (26 September 2008). C# 2008 for Programmers. Pearson Education. p. 40. ISBN 978-0-13-701188-9.
  5. ^ "Jagged Arrays". FunctionX. Retrieved 26 November 2014.
  6. ^ "Lists in Python Demystified". Alvin.io. Retrieved 31 January 2016.