Separate CSV to stucture array by a specified field
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Greetings!
I have a CSV file with the following contents:
"x", "y", "ZLEVEL"
15566.071598095354, 654.75138415898618, A
15730.023876579013, 660.38875580774038, A
15772.038140720921, 665.0524486236709, A
15861.67702561093, 669.09878141965692, B
15964.77015716501, 675.05706329613804, B
16054.020545106847, 683.1063847011992, B
16118.583970776759, 690.87616533615892, B
16231.136948002502, 695.99923622422557, C
16344.66294729244, 700.25827295850286, C
16400.372270382126, 705.20613829250306, C
16486.242397353868, 709.25627232144143, C
16564.589258300024, 715.96303745505884, C
16624.046537611983, 723.13271402537612, C
16752.728644676041, 727.80842778700935, C
16860.248868173338, 732.05753736629867, C
16906.759450074052, 736.81366143388732, C
I intent to create a 3 by 1 struct array with two fields XYData (matrix) and ZLEVEL (string), which holds the CSV data separated by ZLEVEL field and XYData matrix holds X and Y in its original CSV order.
Can you suggest me a nifty way (using built-in MATLAB functions) to do this please?
Thank you.
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채택된 답변
Walter Roberson
2015년 10월 19일
If you have R2014b or later you can use tableread() and then group the entries by ZLevel.
But that's because you asked for nifty, not for efficient.
추가 답변 (1개)
Guillaume
2015년 10월 19일
A table probably makes the reading of the file easier but I'm not sure it helps much after that. I don't think unstack is going to work for this.
It's still somewhat simple to do:
%read data with textscan
fid = fopen('somefile.txt', 'rt');
c = textscan(fid, '%f, %f, %s', 'HeaderLines', 1);
fclose(fid);
%or as a table
t = readtable('somefile.txt');
%partition the data,
%using a table here. replace t.x, t.y, t.ZLEVEL, by c{1}, c{2}, c{3} if using textscan
[levels, ~, pos] = unique(t.ZLEVEL); %get partitioning
xygrouped = accumarray(pos, 1:numel(pos), [], @(v) {[t.x(v), t.y(v)]}) %defer to accumarray to do the grouping
sarray = struct('XYData', xygrouped, 'ZLEVEL', levels) %and convert to struct
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Guillaume
2015년 10월 20일
I thought your objective was to create a structure. Note that my example does use a table object.
Your step 1) and 2) are the same as my unique line.
Your step 3) is the same as my accumarray line.
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