Access Data in Nested Structures

This example shows how to index into a structure that is nested within another structure. The general syntax for accessing data in a particular field is

结构体Name(index).nestedStructName(index).fieldName(indices)

When a structure is scalar (1-by-1), you do not need to include the indices to refer to the single element. For example, create a scalar structures, where fieldnis a nested scalar structure with fieldsa,b, andc:

s.n.a = ones(3); s.n.b = eye(4); s.n.c = magic(5);

Access the third row of fieldb:

third_row_b = s.n.b(3,:)

Variablethird_row_bcontains the third row ofeye(4).

third_row_b = 0 0 1 0

Expandsso that bothsandnare nonscalar (1-by-2):

s(1).n(2).a = 2*ones(3); s(1).n(2).b = 2*eye(4); s(1).n(2).c = 2*magic(5); s(2).n(1).a ='1a';s(2).n(2).a =“2”;s(2).n(1).b ='1b';s(2).n(2).b ='2b';s(2).n(1).c ='1c';(2) . (2) . c ='2c';

Structuresnow contains the data shown in the following figure.

Access part of the array in fieldbof the second element innwithin the first element ofs:

part_two_eye = s(1).n(2).b(1:2,1:2)

This returns the 2-by-2 upper left corner of2*eye(4):

part_two_eye = 2 0 0 2

Access Data in Nested Structures

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