{}
Denotes a vector, matrix, string, or string array definition.
Syntax
{expr_1,expr_2,…,expr_n}
Operand
 expr_1, expr_2, ..., expr_n
 A set of valid scalar, vector, matrix, string, or string array expressions.
Example
Expression  Result 

{1} 
1 
{1, 1+1,1+1+1} 
1, 2, 3 
{a=2}

{0, 3}, {1, 0} 
{{"This", "is ", "a ", "test"}} 
{"This ","is ", "a ", "test"} 
Comments
If there is only one element within the braces, the result is a scalar expression. Multiple elements define a vector.
If there is only one vector within the braces, the result is a vector expression. Multiple vectors of the same dimension define a matrix of m rows by n vectors.
If there is only one string within the braces, the result is a string expression. Multiple strings define a string array.