Extracting everything from a structure

37 次查看（过去 30 天）
Jeff
Jeff 2011-6-3
Is there a built in function to extract everything from a structure?
For example if I have a structure:
struct_name.struct_element1 = 7;
struct_name.struct_element2 = 'abc';
Then later I want create variables for every element of struct_name but I'm unaware of how many elements are in "struct_name" and what their names are. I wrote the following code to solve my problem but I feel there might be a more elegant solution or a built in function:
struct_field_names = fieldnames(struct_name);
for k = 1:length(struct_field_names)
eval([struct_field_names{k}, ' =...
struct_name.',struct_field_names{k}, ';']);
end

请先登录，再回答此问题。

采纳的回答

Jeff
Jeff 2011-6-3
Ahh I searched more rigorously and found this discussion:
http://www.mathworks.com/matlabcentral/newsreader/view_thread/30533

更多回答（3 个）

Jan
Jan 2011-6-3
Take this into account:
struct_name.struct_name = 1;
struct_name.data2 = 2;
Now the result of the creation of variables depends on the order of fields - a dangerous programming method.
So follow Oleg's link and avoid the dynamic creation of variables. Using ISFIELD and "dynamic fieldnames" is a more reliable technique.
Oleg Komarov
Oleg Komarov 2011-6-3
Don't do that: http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F
Think if you had 20 fields in the struct, you would end up populating the workspace with 20 different variables which you will have eiter use by manual referencing or by using eval.
Both methods are nightmare, but you're welcome to abuse eval for some time. The problem comes later when you have to mantain your code.
  4 个评论
显示 2更早的评论
Jeff
Jeff 2011-6-3
Good points. I can create a list of variables needed rather than relying on fieldnames and add error handling for needed variables that don't exist. The function suggested on the link I posted below uses "assignin" within a for loop in a function so I believe that eliminates the concern for the assignment creating the iterator variable.
Walter Roberson
Walter Roberson 2011-6-3
The problem isn't in creating the iterator variable: the problem would be that on the next iteration of the loop, the variable you _thought_ you copied from the structure would get overwritten.

请先登录，再进行评论。

Sean de Wolski
Sean de Wolski 2011-6-3
doc struct2cell
?
  2 个评论
Jeff
Jeff 2011-6-3
That does well to get the values but it loses the names of the elements :-(
Sean de Wolski
Sean de Wolski 2011-6-3
The values and their indeces should be all you need, per the FAQ link.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Structures 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by