[index]
Index function.
Syntax
expr [index_1] [index_2]
Operands
- expr
 - A valid vector, matrix, string, or string array expression.
 - index_1
 - Either a scalar expression that describes the position of an element in a vector or vector expression that describes the position of a row of elements in a matrix.
 - index_2
 - An optional scalar or vector expression that describes the position of an element of a matrix.
 
Example
| Expression | Result | 
|---|---|
a = {4, 2, 6,
                                    8}
  | 
                                6 | 
                            
{1, 2, 3, 4} [0] | 
                                1 | 
                            
{2, 4, 6,  8}  [{1, 2}] | 
                                {4,6} | 
                            
{ {1, 2, 3,}, {4, 5, 6} } [1] | 
                                {4, 5, 6} | 
                            
{ {1, 2, 3,}, {4, 5, 6} } [1] [0] | 
                                4 | 
                            
{"The ", "quick ", "brown ", "fox"}
                                    [2] | 
                                "brown" | 
                            
| Expression | Result | 
|---|---|
x = c1.x[0:100:1]
  | 
                                A curve is created which is the first 101 points of
                                        c1. | 
                            
Comments
[index] is the only mathematical function where brackets, [ ], do not indicate optional items. The brackets are part of this function's syntax.
The index function accesses specific elements of a vector or matrix expression.
The first element of a vector is at index zero. index_1 and index_2 must be non-negative and less than the total number of elements in the vector expression.
If expr is a vector, the result is the scalar located at the index_1 position.
If expr is a matrix, the result is the row vector located at the index_1 position. A second index can be used to identify the scalar at the index_2 position of the index_1 vector.
If expr is a string array, the result is the string located at the index_1 position. A second index cannot be used to identify characters within the string array.