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Extract values from a deeply nested Struct for a designated fieldname

version 1.2.0.0 (6.55 KB) by Yung-Yeh Chang
Useful tool for searching and collecting values in a tree data type STRUCT with specific fieldname

310 Downloads

Updated 12 Jun 2017

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STRUCTVAL is a convenient tool that extracts values from a deeply nested Struct for a designated fieldname.
Assuming you have a data set that is constructed with the same property and stored in a struct variable. It may look like:
data.a001.r01.values
data.a001.r02.values
data.a001.r03.values
data.b002.r01.values
data.c003.values
..
..
How can you extract all the values in `values` filed under each subset of `data`?

This is my solution.

[output] = STRUCTVAL(S,fieldname) deeply searches a STRUCT variable for the field values in `fieldname` and collects result in `output`. This function collects any data type but STRUCT. If the data type for the particular field is a struct, it keeps searching down further.

Furthermore, STRUCTVAL is also capable to reconstruct the hierarchical data structure! This is extremely useful when you need to replace a particularly field with new value!

For more information, type "help structval" in the command window to find out.
Example:
>> S.a = 1;
>> S.a.val = 1;
>> S.b.val = 'test';
>> field = 'val';
>> val = structval(S,field)
val =
[1] 'test'

This function is very useful when your data are hidden deeply down a nested STRUCT variable. I used it for collecting results from a Simulink output, which has the form such like data.resultA.signals.values, data.resultB.signals.values....and so forth. Hopefully, it will be useful to you. If you found any problem in the code, please don't hesitate to contact me or leave comments below.

Yung-Yeh Chang Ph.D.
6/12/2017

Cite As

Yung-Yeh Chang (2021). Extract values from a deeply nested Struct for a designated fieldname (https://www.mathworks.com/matlabcentral/fileexchange/50534-extract-values-from-a-deeply-nested-struct-for-a-designated-fieldname), MATLAB Central File Exchange. Retrieved .

MATLAB Release Compatibility
Created with R2017a
Compatible with any release
Platform Compatibility
Windows macOS Linux
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