[Lang][Matlab] Structure Array in Matlab

1. Structure declaration:

s = struct('field1', value1, 'field2', value2, ....) // create structure with fields and appropriate values

s = struct('field1', {}, 'field2', {},...) //create structure with empty values for each field

s = struct // create structure with empty field

s = struct([]) //create empty structure

s = struct

Example 1:

stuMyStruct = struct('color', {'red', 'green', 'yellow'}, 'type', 1)

Results:

stuMyStruct is structure array with:

stuMyStruct(1):

color: 'red'

type: 1

stuMyStruc(2):

color: 'green'

type: 1

stuMyStruct(3):

color: 'yellow'

type: 1

Example 2:

stuMyStruct = struct('color', {'red', 'green', 'yellow'}, 'type', {1, 2, 3})

Results:

stuMyStruct is structure array with:

stuMyStruct(1):

color: 'red'

type: 1

stuMyStruc(2):

color: 'green'

type:2

stuMyStruct(3):

color: 'yellow'

type: 3

Example 3:

stuMyStruct.color

Results:

ans = red

ans = green

ans = yellow

2. Access structure

There are two ways to access structure fields: by specifying field name or by dynamic field name. Here, we mention the dynamic field name because of the easy of the first way.

Example 4:

stuMyStruct = struct('color', 'red', 'type', 1)

strNewField = 'weight';

stuMyStruct.(strNewField) = 100;

Results:

stuMyStruct =

color: 'red'

type: 1

weight: 100

Note: distinguish from this case

stuMyStruct = struct('color', 'red', 'type', 1)

strNewField = 'weight';

stuMyStruct.strNewField = 100;

leads to this result

stuMyStruct =

color: 'red'

type: 1

strNewField : 100

3. Some other functions for field process

fieldnames: list all field name, type and attributes of structure or structure array

setfield: set value to field (very strong)

getfield: get value of specified field (very strong)

isfield: check the existence of a fieldname

orderfields: reorder the fieldnames

rmfield: remove specified fieldname

isstruct: determine whether input is a structure array

Refercences:

[1] Structure for Matlab

[2] Memory Managements for functions and variables

[3] Dynamic field name