6.1.3 Creating Structures

As well as indexing a structure with ".", Octave can create a structure with the struct command. struct takes pairs of arguments, where the first argument in the pair is the fieldname to include in the structure and the second is a scalar or cell array, representing the values to include in the structure or structure array. For example

struct ("field1", 1, "field2", 2)
⇒ ans =
      {
        field1 =  1
        field2 =  2
      }

If the values passed to struct are a mix of scalar and cell arrays, then the scalar arguments are expanded to create a structure array with a consistent dimension. For example

s = struct ("field1", {1, "one"}, "field2", {2, "two"},
        "field3", 3);
s.field1
     ⇒ 
        ans =  1
        ans = one

s.field2
     ⇒
        ans =  2
        ans = two

s.field3
     ⇒
        ans =  3
        ans =  3

If you want to create a struct which contains a cell array as an individual field, you have to put it into another cell array like in the following example:

struct ("field1", {{1, "one"}}, "field2", 2)
     ⇒ ans =
        {
          field1 =
        
        {
          [1,1] =  1
          [1,2] = one
        }
        
          field2 =  2
        }
 

Built-in Function: struct ("field", value, "field", value, …)

Create a structure and initialize its value.

If the values are cell arrays, create a structure array and initialize its values. The dimensions of each cell array of values must match. Singleton cells and non-cell values are repeated so that they fill the entire array. If the cells are empty, create an empty structure array with the specified field names.

If the argument is an object, return the underlying struct.

The function isstruct can be used to test if an object is a structure or a structure array.

Built-in Function: isstruct (expr)

Return 1 if the value of the expression expr is a structure.