Naming individual fields in a struct

Question

mashtine 2014-2-24

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https://ww2.mathworks.cn/matlabcentral/answers/118845-naming-individual-fields-in-a-struct

编辑： Walter Roberson 2014-2-24

采纳的回答： Walter Roberson

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Hi everyone,

I have this block of code:

HWFiles = {'midas_wind_197901-197912.txt',............'midas_wind_201301-201312.txt'};
for k=1:numel(HWFiles);                                                                                                                             
    fid = fopen(HWFiles{k}, 'r');                                                                                                                  
    tmp = textscan(fid,'%s %*s %*f %*f %*s %*f %f %*f %f %f %f %f %f %*f %*f %*f %*f %*f %*f %*f %*f %*s %*f', 'Delimiter',',');                  
      HWData(k).data = tmp ;                                                                                                                         
      fclose(fid);
  end

Not pasting well sorry. HWData becomes a 1 x 35 struct and I wanted to change each field name to the year from the file, eg 1979, 1980 .... 2013. Any ideas with this?

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Answer 1

Walter Roberson 2014-2-24

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Are you asking to create a structure of length 1, HWData, with field names 1979, 1980, and so on? If so then you cannot do that as field names must start with a letter. If you wanted to be able to look up by year then you could use a common prefix such as 'Y', so Y1979, Y1980, and so on. Or you could use containers.map

TO use the prefix,

prefix = 'Y';

and in the loop,

filename = HWFiles{k};
underpos = find(filename, '_', 1, 'last');
fieldname = [prefix filename(underpos+1:underpos+3)];
HWData.(fieldname) = tmp;

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mashtine 2014-2-24

However, I believe indexing this in a loop to manipulate and work with the data is probably a bit too complicated (or perhaps I just don't know it yet)

Walter Roberson 2014-2-24

编辑：Walter Roberson 2014-2-24

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Opps, should have had

underpos = find(filename == '_', 1, 'last');

Indexing by a non-consecutive number (eg. year) to work in a loop is going to be very nearly as much trouble.

Recall that you can use fieldnames() to get the names of the fields. And sort() of a cell array of strings would give the fieldnames sorted numerically provided they were all the same length.

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Answer 2

Image Analyst 2014-2-24

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If you have R2013b, why not use a table. You can use struct2table to convert your structure to a possibly more convenient table. Table is a brand new data type. http://www.mathworks.com/help/matlab/ref/struct2table.html