Creating a data structure by a loop.

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Ben
Ben 2016-7-17
评论： Ben 2016-7-17
Hi everyone, I found some code to make a data structure in matlab, my code is below: So far I have imported a bunch of data from excel as 177x10 matrices (ignore the wavelengths one). So I am trying to create data structures where I can start each structure with the names us_mari., us_urban., us_rural. and us_tropo. and have ten different column matrices within each data structure using field names found in the list_nam. My code below will give one of the structures I want:
wavelengths=xlsread('USstandard_collection.xlsx','sheet1','B14:B190');
usmari_data=xlsread('USstandard_collection.xlsx','sheet1','C14:L190');
usrural_data=xlsread('USstandard_collection.xlsx','sheet1','Q14:Z190');
usurban_data=xlsread('USstandard_collection.xlsx','sheet1','AU14:BD190');
ustropo_data=xlsread('USstandard_collection.xlsx','sheet1','AF14:AO190');
list_nam = {'hwy101_left','beach','field_of_rocks','sears','la_cumbre_golf_course',...
'dirt_patch_right','hwy101_rightside','parking_lot_flower','middle_school_parking_lot',...
'stadium'}
for iter=1:length(list_nam)
us_mari.(list_nam{iter})=usmari_data(:,iter);
end
result:
>> us_mari
us_mari =
hwy101_left: [177x1 double]
beach: [177x1 double]
field_of_rocks: [177x1 double]
sears: [177x1 double]
la_cumbre_golf_course: [177x1 double]
dirt_patch_right: [177x1 double]
hwy101_rightside: [177x1 double]
parking_lot_flower: [177x1 double]
middle_school_parking_lot: [177x1 double]
stadium: [177x1 double]
My current code only works for the mari data and I also want to do it over the other three: urban, rural, and tropo, so my code I'm working on so far to create 4 datasets in a loop is below:
name_of_data_structure = {'us_mari', 'us_rural', 'us_urban', 'us_tropo'}
data_matrix = {usmari_data, usrural_data, usurban_data, ustropo_data}
for itt = 1:length(name_of_data_structure)
for iter=1:length(list_nam)
name_of_data_structure(itt).(list_nam{iter})=data_matrix(itt)(:,iter);
end
end
but I get the following error:
Error: File: spectral_data.m Line: 21 Column: 54
()-indexing must appear last in an index expression.
Thanks for all the help and if you see anything else wrong, please let me know! Ben

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回答（1 个）

Azzi Abdelmalek
Azzi Abdelmalek 2016-7-17
编辑：Azzi Abdelmalek 2016-7-17
Use {}
name_of_data_structure(itt).(list_nam(iter))=data_matrix{itt}(:,iter}
  2 个评论
Ben
Ben 2016-7-17
Thank you that solved that issue, I just have one more question, now I get this error,
Field assignment to a non-structure array object.
Error in spectral_data (line 21)
name_of_data_structure(itt).(list_nam{iter})=data_matrix{itt}(:,iter);
Thank you, for what you have done so far, it has helped a lot!
Ben
Ben 2016-7-17
I actually got it to work for the most part using this.
name_of_data_structure = {'us_mari', 'us_rural', 'us_urban', 'us_tropo'}
data_matrix = {usmari_data, usrural_data, usurban_data, ustropo_data}
for itt = 1:length(name_of_data_structure)
name_of_data_structure{itt} = struct()
for iter=1:length(list_nam)
name_of_data_structure{itt}.(list_nam{iter})=data_matrix{itt}(:,iter);
end
end
but for some reason, in order to get anything I need to write name_of_data_structure{1}.beach, when I wanted for example was us_rural.beach
Thanks, Ben

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