How to extract data from a multi layered structure

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012786534
012786534 2019-8-22
编辑： Stephen23 2019-8-23
Hi,
I have a multi-layered structure A that include 3 structures (a, b and c) and and all of them contain 10 fieldnames with 10 rows and every cell further contains 10 double numbers mixed with nans.
Doing
A.b.fieldname1
yields the content of the first cell (10 double), but I cant seem to to be able to extract the entire fielname. Doing
c = cell2mat(struct2cell(A.b.fieldname1(1,1)))
yields the following error: Expected one output from a curly brace or dot indexing expression, but there were 10 results.
So how can I extract the data from this multi-layered structure ?
Thank you,
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012786534
012786534 2019-8-22
My apologies. My attempts at simplifying reality has caused more harm than good.
Lets start over. I have the structure attached here.
How can i calculate the minimum of a given field (min_temp for example) ? Thats why I want to extract the data.
Stephen23
Stephen23 2019-8-22
编辑：Stephen23 2019-8-22
Your structure is non-scalar:
>> load('PMAN_climatology.mat')
>> size(pman_climatology)
ans =
1 14
That explains the error message you give in your question.
Not only that, but none of its fields contain nested structures:
>> F = @(s)any(structfun(@isstruct,s));
>> arrayfun(F,pman_climatology)
ans =
0 0 0 0 0 0 0 0 0 0 0 0 0 0
"How can i calculate the minimum of a given field (min_temp for example)?"
You don't define "the minimum" for mutliple vectors: do you want the global minimum, or the minimum of each vector, or the minimum of each column when the vectors are concatenated into one matrix, or some other minimum?

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回答（1 个）

Stephen23
Stephen23 2019-8-22
编辑：Stephen23 2019-8-23
"How can i calculate the minimum of a given field (min_temp for example) ?"
You do not define what "the minimum" means for multiple vectors, which makes it hard to guesss what output you expect...
Method one: comma-separated list and cellfun:
https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html
https://www.mathworks.com/matlabcentral/answers/320713-how-to-operate-on-comma-separated-lists
For example:
>> vec = cellfun(@min,{pman_climatology.min_temp})
vec =
1.0000 4.6000 3.0000 3.0000 2.1000 2.5000 2.0000 2.0000 6.5000 1.5000 1.0000 1.5000 4.1000 1.0000
That gives the minimum value of the field min_temp for each element of the structure pman_climatology. Compare with the first few elements of pman_climatology:
>> min(pman_climatology(1).min_temp)
ans =
1
>> min(pman_climatology(2).min_temp)
ans =
4.6000
>> min(pman_climatology(3).min_temp)
ans =
3
Method two: anonymous function and arrayfun:
>> F = @(s)min(s.min_temp);
>> arrayfun(F,pman_climatology)

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