textscan: strings and variables

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michael
michael on 18 Dec 2021
Edited: Walter Roberson on 18 Dec 2021
Hi,
I have some csv file which contains numbers and strings (example below)
The column headers are in seperate file from the data, but can be merged to the same one.
I'd like to import the data with textscan (as I have old version of MATLAB-R14) and assign it to some variable (which is the column name) for further analysis.
How can I do that?
For numbers I use something like
eval (column name = [column data])
For time: as it with same length - I also don't have any issue (as I can split the data into 3 coulns and later handle it with time related functions).
But what about other ones where the string values are with variable length (like RATE or STATUS columns as in the example)?
  3 Comments
Walter Roberson
Walter Roberson on 18 Dec 2021
https://blogs.mathworks.com/loren/2005/12/13/use-dynamic-field-references/
Dynamic field names existed in your release (R13 introduction), and for earlier releases use setfield()

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Answers (1)

Stephen23
Stephen23 on 18 Dec 2021
Edited: Stephen23 on 18 Dec 2021
Perhaps something like this, a more robust approach using a structure (this still requires that the headers are valid MATLAB names):
opt = {'Delimiter',','};
fid = fopen('test.txt','rt');
hdr = fgetl(fid);
tmp = textscan(fid,'%s%f%f%s%f%s',opt{:});
fclose(fid);
hdr = regexp(hdr,'[^,]+','match');
out = cell2struct(tmp,hdr,2)
out = struct with fields:
TIME: {3×1 cell} LAT: [3×1 double] LON: [3×1 double] STATUS: {3×1 cell} ALT: [3×1 double] RATE: {3×1 cell}
out.TIME
ans = 3×1 cell array
{'06:02:00'} {'06:02:01'} {'06:02:02'}
out.LAT
ans = 3×1
30.0010 30.0020 30.0040
out.LON
ans = 3×1
31.0020 31.0030 31.0040
  1 Comment
Walter Roberson
Walter Roberson on 18 Dec 2021
Edited: Walter Roberson on 18 Dec 2021
after getting hdr, pass it through genvarname(), which will convert invalid names (such as containing spaces or punctuation) into valid names, and will further modify names to ensure that they are unique (in case two columns has the same name, one will be given a suffix)

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