Syntax

Array dimensions

The following list contains syntax examples of how to determine the dimensions (index of the first element, the last element or the size in elements).

Some languages index from zero. Some index from one. Some carry no such restriction, or even allow indexing by any enumerated type, not only integers.

Indexing

The following list contains syntax examples of how to access a single element of an array.

Slicing

The following list contains syntax examples of how a range of element of an array can be accessed.

In the following table:

• first – the index of the first element in the slice
• last – the index of the last element in the slice
• end – one more than the index of last element in the slice
• len – the length of the slice (= end - first)
• step – the number of array elements in each (default 1)

Array system cross-reference list

Vectorized array operations

Some compiled languages such as Ada and Fortran, and some scripting languages such as IDL, MATLAB, and S-Lang, have native support for vectorized operations on arrays. For example, to perform an element by element sum of two arrays, a and b to produce a third c, it is only necessary to write

In addition to support for vectorized arithmetic and relational operations, these languages also vectorize common mathematical functions such as sine. For example, if x is an array, then

will result in an array y whose elements are sine of the corresponding elements of the array x.

Vectorized index operations are also supported. As an example,

is how one would use Fortran to create arrays from the even and odd entries of an array. Another common use of vectorized indices is a filtering operation. Consider a clipping operation of a sine wave where amplitudes larger than 0.5 are to be set to 0.5. Using S-Lang, this can be done by

Mathematical matrix operations

References

1. "ECMAScript® 2025 Language Specification". https://tc39.es/ecma262/multipage/indexed-collections.html#sec-array.prototype.at ↩

2. "ECMAScript® 2025 Language Specification". https://tc39.es/ecma262/multipage/indexed-collections.html#sec-array.prototype.at ↩

3. "Programming in Lua : 11.1". https://www.lua.org/pil/11.1.html ↩

4. "Nim Tutorial (Part I)". https://nim-lang.org/docs/tut1.html#advanced-types-arrays ↩

5. XPath/XQuery has two kinds of arrays. Sequences (1,2,3) which cannot nest and in the XPath/XQuery 3.1 version arrays array { 1,2,3} or [1,2,3] which can. ↩

6. The index may be a negative number, indicating the corresponding number of places before the end of the array. ↩

7. The index may be a negative number, indicating the corresponding number of places before the end of the array. ↩

8. The index may be a negative number, indicating the corresponding number of places before the end of the array. ↩

9. The index may be a negative number, indicating the corresponding number of places before the end of the array. ↩

10. The index may be a negative number, indicating the corresponding number of places before the end of the array. ↩

11. The index may be a negative number, indicating the corresponding number of places before the end of the array. ↩

12. XPath/XQuery has two kinds of arrays. Sequences (1,2,3) which cannot nest and in the XPath/XQuery 3.1 version arrays array { 1,2,3} or [1,2,3] which can. ↩

13. XPath/XQuery has two kinds of arrays. Sequences (1,2,3) which cannot nest and in the XPath/XQuery 3.1 version arrays array { 1,2,3} or [1,2,3] which can. ↩

14. XPath/XQuery has two kinds of arrays. Sequences (1,2,3) which cannot nest and in the XPath/XQuery 3.1 version arrays array { 1,2,3} or [1,2,3] which can. ↩

15. The index may be a negative number, indicating the corresponding number of places before the end of the array. ↩

16. "Eiffeldoc : ARRAY". http://smarteiffel.loria.fr/libraries/api/lib.d/storage.d/loadpath.se.d/collection.d/ARRAY/ANY.html ↩

17. Slices for multidimensional arrays are also supported and defined similarly. ↩

18. Slices of the type first:last:step are also supported. ↩

19. last or end may be a negative number, indicating to stop at the corresponding number of places before the end of the array. ↩

20. More generally, for 1-d arrays Perl and S-Lang allow slices of the formarray[indices], where indices can be a range such mentioned in footnote 2 or an explicit list of indices, e.g., '[0,9,3,4]', or a mix of both, e.g., A[[[0:3]],7,9,[11:2:-3]]]. /wiki/Perl ↩

21. last or end may be a negative number, indicating to stop at the corresponding number of places before the end of the array. ↩

22. Slices for multidimensional arrays are also supported and defined similarly. ↩

23. Slices for multidimensional arrays are also supported and defined similarly. ↩

24. Slices of the type first:last:step are also supported. ↩

25. Slices for multidimensional arrays are also supported and defined similarly. ↩

26. More generally, for 1-d arrays Perl and S-Lang allow slices of the formarray[indices], where indices can be a range such mentioned in footnote 2 or an explicit list of indices, e.g., '[0,9,3,4]', or a mix of both, e.g., A[[[0:3]],7,9,[11:2:-3]]]. /wiki/Perl ↩

27. Slices for multidimensional arrays are also supported and defined similarly. ↩

28. Slices of the type first:last:step are also supported. ↩

29. last or end may be a negative number, indicating to stop at the corresponding number of places before the end of the array. ↩

30. Slices for multidimensional arrays are also supported and defined similarly. ↩

31. Slices of the type first:last:step are also supported. ↩

32. More generally, for 1-d arrays Perl and S-Lang allow slices of the formarray[indices], where indices can be a range such mentioned in footnote 2 or an explicit list of indices, e.g., '[0,9,3,4]', or a mix of both, e.g., A[[[0:3]],7,9,[11:2:-3]]]. /wiki/Perl ↩

33. last or end may be a negative number, indicating to stop at the corresponding number of places before the end of the array. ↩

34. C# 8.0 proposed feature (as of 29 August 2019[update]) /wiki/C_Sharp_(programming_language) ↩

35. "Ranges - C# 8.0 language proposals". Microsoft Docs. Microsoft. Retrieved 29 August 2019. https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-8.0/ranges ↩

36. "Lua 5.3 Reference Manual". www.lua.org. Retrieved 2022-04-02. https://www.lua.org/manual/5.3/manual.html#pdf-table.move ↩

37. The index type can be a freely chosen integer type, enumerated type, or character type. For arrays with non-compact index types see: Associative array /wiki/Integer_(computer_science) ↩

38. The default base index is the lowest value of the index type used ↩

39. Size can only be chosen on initialization after which it is fixed. ↩

40. This list is strictly comparing language features. In every language (even assembly language) it is possible to provide improved array handling via add on libraries. This language has improved array handling as part of its standard library /wiki/Assembly_language ↩

41. ALGOL 68 arrays must be subscripted (and sliced) by type INT. However a hash function could be used to convert other types to INT. e.g. name[hash("string")] ↩

42. The indexing base can be 0 or 1 as per the System Variable ⎕IO. This value may apply to the whole "workspace", or be localized to a user-defined function or a single primitive function by use of the Variant operator (⍠). ↩

43. Size can only be chosen on initialization after which it is fixed. ↩

44. Because C does not bound-check indices, a pointer to the interior of any array can be defined that will symbolically act as a pseudo-array that accommodates negative indices or any integer index origin. ↩

45. Size can only be chosen on initialization after which it is fixed. ↩

46. C99 allows for variable size arrays; however there is almost no compiler available to support this new feature ↩

47. Size can only be chosen on initialization when memory is allocated on the heap, as distinguished from when it is allocated on the stack. This note need not be made for a language that always allocates arrays on the heap. ↩

48. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

49. Size can only be chosen on initialization after which it is fixed. ↩

50. C99 allows for variable size arrays; however there is almost no compiler available to support this new feature ↩

51. Size can only be chosen on initialization when memory is allocated on the heap, as distinguished from when it is allocated on the stack. This note need not be made for a language that always allocates arrays on the heap. ↩

52. This list is strictly comparing language features. In every language (even assembly language) it is possible to provide improved array handling via add on libraries. This language has improved array handling as part of its standard library /wiki/Assembly_language ↩

53. Because C does not bound-check indices, a pointer to the interior of any array can be defined that will symbolically act as a pseudo-array that accommodates negative indices or any integer index origin. ↩

54. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

55. Size can only be chosen on initialization when memory is allocated on the heap, as distinguished from when it is allocated on the stack. This note need not be made for a language that always allocates arrays on the heap. ↩

56. The base can be changed when initializing with System.Array.CreateInstance (which returns System.Array), but not when using the language syntax. Arrays with non-zero base indices are not the same type as those with zero base indices and cannot be manipulated using language syntax (the GetValue and SetValue methods must be used instead) or downcast to a specific type (T[] in C#, or T() in VB.NET), preventing breakage of code assuming base indices of zero. /wiki/C_Sharp_(programming_language) ↩

57. Size can only be chosen on initialization when memory is allocated on the heap, as distinguished from when it is allocated on the stack. This note need not be made for a language that always allocates arrays on the heap. ↩

58. Allows creating fixed-size arrays in "unsafe" code, allowing enhanced interoperability with other language /wiki/Interoperability ↩

59. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

60. COBOL arrays may be indexed with "INDEX" types, distinct from integer types ↩

61. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

62. While COBOL only has arrays-of-arrays, array elements can be accessed with a multi-dimensional-array-like syntax, where the language automatically matches the indexes to the arrays enclosing the item being referenced ↩

63. COBOL provides a way to specify that the usable size of an array is variable, but this can never be greater than the declared maximum size, which is also the allocated size ↩

64. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

65. Most Common Lisp implementations allow checking to be selectively disabled ↩

66. Associative Arrays - D Programming Language http://dlang.org/hash-map.html ↩

67. Behaviour can be tuned via compiler switches. As in DMD 1.0 bounds are checked in debug mode and unchecked in release mode for efficiency ↩

68. The base can be changed when initializing with System.Array.CreateInstance (which returns System.Array), but not when using the language syntax. Arrays with non-zero base indices are not the same type as those with zero base indices and cannot be manipulated using language syntax (the GetValue and SetValue methods must be used instead) or downcast to a specific type (T[] in C#, or T() in VB.NET), preventing breakage of code assuming base indices of zero. /wiki/C_Sharp_(programming_language) ↩

69. Size can only be chosen on initialization when memory is allocated on the heap, as distinguished from when it is allocated on the stack. This note need not be made for a language that always allocates arrays on the heap. ↩

70. Allows creating fixed-size arrays in "unsafe" code, allowing enhanced interoperability with other language /wiki/Interoperability ↩

71. Size can only be chosen on initialization after which it is fixed. ↩

72. FreeBASIC supports both variable array lengths and fixed length arrays. Arrays declared with no index range are created as variable-length arrays, while arrays with a declared range are created as fixed-length arrays ↩

73. Almost all Fortran implementations offer bounds checking options via compiler switches. However by default, bounds checking is usually turned off for efficiency ↩

74. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

75. While Golang's Array type is not dynamically sized, the data type Slice is dynamically-sized and is much more common in use than arrays. https://tour.golang.org/moretypes/7 ↩

76. Haskell arrays (Data.Array) allow using any type which is an instance of Ix as index type. So a custom type can be defined and used as an index type as long as it instances Ix. Also, tuples of Ix types are also Ix types; this is commonly used to implement multi-dimensional arrays ↩

77. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

78. Size can only be chosen on initialization after which it is fixed. ↩

79. Size can only be chosen on initialization after which it is fixed. ↩

80. This list is strictly comparing language features. In every language (even assembly language) it is possible to provide improved array handling via add on libraries. This language has improved array handling as part of its standard library /wiki/Assembly_language ↩

81. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

82. Size can only be chosen on initialization after which it is fixed. ↩

83. In these languages, one can access or write to an array index greater than or equal to the length of the array, and the array will implicitly grow to that size. This may appear at first as if the bounds are not checked; however, the bounds are checked to decide to grow the array, and you do not have unsafe memory access like you do in C. ↩

84. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

85. By specifying a base index, arrays at an arbitrary base can be created. However, by default, Lua's length operator does not consider the base index of the array when calculating the length. This behavior can be changed via metamethods. ↩

86. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

87. At least 2 dimensions (scalar numbers are 1×1 arrays, vectors are 1×n or n×1 arrays). ↩

88. "Nim Tutorial (Part I)". https://nim-lang.org/docs/tut1.html#advanced-types-arrays ↩

89. "Nim Compiler User Guide". https://nim-lang.org/docs/nimc.html ↩

90. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

91. "Vectorization - R-style logical vector operation in Nim". https://stackoverflow.com/questions/53084192/r-style-logical-vector-operation-in-nim ↩

92. This list is strictly comparing language features. In every language (even assembly language) it is possible to provide improved array handling via add on libraries. This language has improved array handling as part of its standard library /wiki/Assembly_language ↩

93. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

94. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

95. Size can only be chosen on initialization after which it is fixed. ↩

96. The default base index is the lowest value of the index type used ↩

97. Many implementations (Turbo Pascal, Object Pascal (Delphi), Free Pascal) allow the behaviour to be changed by compiler switches and in-line directives /wiki/Turbo_Pascal ↩

98. Varies by implementation. Newer implementations (Free Pascal, Object Pascal (Delphi)) allow heap-based dynamic arrays. /wiki/Free_Pascal ↩

99. In these languages, one can access or write to an array index greater than or equal to the length of the array, and the array will implicitly grow to that size. This may appear at first as if the bounds are not checked; however, the bounds are checked to decide to grow the array, and you do not have unsafe memory access like you do in C. ↩

100. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

101. Standard Perl array data types do not support vectorized operations as defined here. However, the Perl Data Language extension adds array objects with this ability. /wiki/Perl ↩

102. In these languages, one can access or write to an array index greater than or equal to the length of the array, and the array will implicitly grow to that size. This may appear at first as if the bounds are not checked; however, the bounds are checked to decide to grow the array, and you do not have unsafe memory access like you do in C. ↩

103. PHP's "arrays" are associative arrays. You can use integers and strings as the keys (indexes); floats can also be used as the key but are truncated to integers. There is not really any "base index" or "bounds" ↩

104. PHP's "arrays" are associative arrays. You can use integers and strings as the keys (indexes); floats can also be used as the key but are truncated to integers. There is not really any "base index" or "bounds" ↩

105. PHP's "arrays" are associative arrays. You can use integers and strings as the keys (indexes); floats can also be used as the key but are truncated to integers. There is not really any "base index" or "bounds" ↩

106. Size can be chosen when the array is declared, or when it is allocated, after which it is fixed. ↩

107. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

108. The standard Python array type, list, does not support vectorized operations as defined here. However, the numpy extension adds array objects with this ability /wiki/Python_(programming_language) ↩

109. By specifying a base index, arrays at an arbitrary base can be created. However, by default, Lua's length operator does not consider the base index of the array when calculating the length. This behavior can be changed via metamethods. ↩

110. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

111. In these languages, one can access or write to an array index greater than or equal to the length of the array, and the array will implicitly grow to that size. This may appear at first as if the bounds are not checked; however, the bounds are checked to decide to grow the array, and you do not have unsafe memory access like you do in C. ↩

112. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

113. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

114. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

115. Behaviour can be tuned via compiler switches. As in DMD 1.0 bounds are checked in debug mode and unchecked in release mode for efficiency ↩

116. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

117. Size can only be chosen on initialization after which it is fixed. ↩

118. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

119. Size can only be chosen on initialization after which it is fixed. ↩

120. This list is strictly comparing language features. In every language (even assembly language) it is possible to provide improved array handling via add on libraries. This language has improved array handling as part of its standard library /wiki/Assembly_language ↩

121. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

122. The class Array is fixed-size, but OrderedCollection is dynamic ↩

123. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

124. Microsoft QBASIC, QuickBASIC, Visual Basic, and VBA all had/have the ability to specify Option Base 1, which caused all arrays in the module to default starting at 1 instead of 0. Support for Option Base was phased out in Visual Basic (.NET). In various Microsoft BASIC implementations, arrays can be DIMensioned using to to specify the minimum and maximum index values (e.g. DIM MyArray(2 to 50) AS STRING would have the first index at 2 instead of the default). /wiki/QuickBASIC ↩

125. Microsoft QBASIC, QuickBASIC, Visual Basic, and VBA all had/have the ability to specify Option Base 1, which caused all arrays in the module to default starting at 1 instead of 0. Support for Option Base was phased out in Visual Basic (.NET). In various Microsoft BASIC implementations, arrays can be DIMensioned using to to specify the minimum and maximum index values (e.g. DIM MyArray(2 to 50) AS STRING would have the first index at 2 instead of the default). /wiki/QuickBASIC ↩

126. The base can be changed when initializing with System.Array.CreateInstance (which returns System.Array), but not when using the language syntax. Arrays with non-zero base indices are not the same type as those with zero base indices and cannot be manipulated using language syntax (the GetValue and SetValue methods must be used instead) or downcast to a specific type (T[] in C#, or T() in VB.NET), preventing breakage of code assuming base indices of zero. /wiki/C_Sharp_(programming_language) ↩

127. XPath/XQuery has two kinds of arrays. Sequences (1,2,3) which cannot nest and in the XPath/XQuery 3.1 version arrays array { 1,2,3} or [1,2,3] which can. ↩

128. Allows arrays of arrays which can be used to emulate most—but not all—aspects multi-dimensional arrays ↩

129. Ch numerical features http://www.softintegration.com/products/features/ch_vs_matlab.html ↩