访问结构数据(matlab) [英] access struct data (matlab)
问题描述
a= struct('a1',{1,2,3},'a2',{4,5,6})
如何获取1的值;
我尝试使用返回错误的a.a1 {1}
I try to use a.a1{1} which return errors
>> a.a1{1}
??? Field reference for multiple structure elements that is followed by more reference blocks is an
error.
如何访问1?谢谢.
修改
A = struct{'a1',[1 2 3],'a2',[4 5 6]}
如何访问1.我使用A(1).a1
,但得到1 2 3
How can I access 1. I use A(1).a1
but I get 1 2 3
推荐答案
您必须改为:
a(1).a1
之所以如此,是因为用于创建结构的代码实际上创建了一个三元素结构数组,其中第一个数组元素包含a1: 1
和a2: 4
,第二个数组元素包含a1: 2
和a2: 5
,第三个数组元素包含a1: 3
和a2: 6
.
The reason why is because the code you use to create your structure actually creates a 3-element structure array where the first array element contains a1: 1
and a2: 4
, the second array element contains a1: 2
and a2: 5
, and the third array element contains a1: 3
and a2: 6
.
当您像以前一样在调用 STRUCT 时使用花括号{}
时, MATLAB假定您要创建一个结构数组,在其中将单元格的内容分配到整个结构数组元素中.相反,如果您要创建一个单个的1比1结构元素,其中的字段包含单元格数组,则必须添加一组额外的花括号来包围您的单元格数组,如下所示:
When you use curly braces {}
in a call to STRUCT like you did, MATLAB assumes you are wanting to create a structure array in which you distribute the contents of the cells across the structure array elements. If you instead want to create a single 1-by-1 structure element where the fields contain cell arrays, you have to add an additional set of curly braces enclosing your cell arrays, like so:
a = struct('a1',{{1,2,3}},'a2',{{4,5,6}});
然后您的原始a.a1{1}
将可用.
如果您使用数字数组而不是单元格数组创建结构,就像这样:
If you create your structure using numeric arrays instead of cell arrays, like so:
A = struct('a1',[1 2 3],'a2',[4 5 6]);
然后您可以按以下方式访问值1:
Then you can access the value of 1 as follows:
A.a1(1)
有关在MATLAB中使用结构的更多信息,请查看此文档页面
For further information about working with structures in MATLAB, check out this documentation page.
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