In Matlab I need to generate one cell of data, that I had missed previously when I had run the program before, to an excel file. Unfortunately, when I try to specify the cell to write in xlswrite and run the program, it deletes the entire excel spreadsheet and only replaces that one generated cell. How do I go about adding one cell to an existing excel file without overwriting the entire file?
%// data is gathered and stored in predefined variables dice34, HD34, and MAE34.
%// files specified have already been created and have been added data before.
rangeData = 'A7';
D = {dice34};
H = {HD34};
M = {MAE34};
fileNameD = 'DiceCoefficientReformatted34.xlsx';
fileNameH = 'HausdorffDistanceReformatted34.xlsx';
fileNameM = 'MeanAbsoluteErrorReformatted34.xlsx';
sheet = 'Sheet1';
xlswrite(fileNameD, D, sheet, rangeData);
xlswrite(fileNameH, H, sheet, rangeData);
xlswrite(fileNameM, M, sheet, rangeData);
Related
I'm trying to load an external CSV file using MATLAB.
I managed to download it using webread, but I only need a subset of the columns.
I tried
Tb = webread('https://datahub.io/machine-learning/iris/r/iris.csv');
X = [sepallength sepalwidth petallength petalwidth];
But I cannot form X this way because the names are not recognized. How can I create X correctly?
The line
Tb = webread('https://datahub.io/machine-learning/iris/r/iris.csv');
Produces a table object with column names you later try to access as if they were workspace variables - which they aren't. Instead, you should modify your code to use:
X = [Tb.sepallength Tb.sepalwidth Tb.petallength Tb.petalwidth];
I am running a MATLAB program and storing the results in two matrices. For each run of the program, those matrices are written to the same .csv file.
How can I continue to store data to the same file for future runs of the program? Is there a function that checks for data already being present to avoid overwriting cells?
t = 0.0001*[0:70];
v = B_2*R_R.*exp(-alpha.*t).*sin(omega_d.*t);
tv = [t; v].';
csvwrite('thedata.csv',tv,3,0)
I couldn't resist rewriting your code a bit.
This should be equivalent to what you have, and print both vectors to thedata.csv.
t = 0.0001*[0:70];
v = B_2*R_R.*exp(-alpha.*t).*sin(omega_d.*t);
tv = [t; v].';
csvwrite('thedata.csv',tv,3,0)
Due to the way csv-files are stored, you can only append data at the end of the file, which happens to be the bottom row, not the last column. What you should do, is concatenate all data before writing to the csv-file. That way you avoid multiple calls to csvwrite or dlmwrite (they are time consuming).
If that's impossible, then I suggest reading the data from the csv-file, using csvread, append the new data to the data you retrieve, and write it all back again.
csvwrite('thedata.csv',tv)
mydata = csvread('thedata.csv');
mydata2 = [mydata, tv2];
csvwrite('thedata.csv',mydata2)
I have data stored in the .tdms format, gathering the data of many sensors, measured every second, every day. A new tdms file is created every day, and stored in a folder per month. Using the convertTDMS function, I have converted these tdms files to mat files.
As there are some errors in some of the measurements(e.g. negative values which can not physically occur), I have performed some corrections by loading one mat file at a time, do the calculations and then save the data into the original .mat file.
However, when I try to do what I described above in a loop (so: load .mat in folder, do calculations on one mat file (or channel therein), save mat file, repeat until all files in the folder have been done), I end up running into trouble with the limitations of the save function: so far I save all variables (or am unable to save) in the workspace when using the code below.
for k = 1:nFiles
w{k,1} = load(wMAT{k,1});
len = length(w{k,1}.(x).(y).(z));
pos = find(w{k,1}.(x).(y).(z)(1,len).(y)<0); %Wind speed must be >0 m/s
for n = 1:length(pos)
w{k,1}.(x).(y).(z)(1,len).(y)(pos(n)) = mean([w{k,1}.(x).(y).(z)(1,len).(y)(pos(n)+1),...
w{k,1}.(x).(y).(z)(1,len).(y)(pos(n)-1)],2);
end
save( name{k,1});
%save(wMAT{k,1},w{k,1}.(x),w{k,1}.ConvertVer,w{k,1}.ChanNames);
end
A bit of background information: the file names are stored in a cell array wMAT of length nFiles in the folder. Each cell in the cell array wMAT stores the fullfile path to the mat files.
The data of the files is loaded and saved into the cell array w, also of length nFiles.
Each cell in "w" has all the data stored from the tdms to mat conversion, in the format described in the convertTDMS description.
This means: to get at the actual data, I need to go from the
cell in the cell array w{k,1} (my addition)
to the struct array "ConvertedData" (Structure of all of the data objects - part of convertTDMS)
to the struct array below called "Data" (convertTDMS)
to the struct array below called "MeasuredData" (convertTDMS) -> at this level, I can access the channels which store the data.
to finally access/manipulate the values stored, I have to select a channel, e.g. (1,len), and then go via the struct array to the actual values (="Data"). (convertTDMS)
In Matlab format, this looks like "w{1, 1}.ConvertedData.Data.MeasuredData(1, len).Data(1:end)" or "w{1, 1}.ConvertedData.Data.MeasuredData(1, len).Data".
To make typing easier, I took
x = 'ConvertedData';
y = 'Data';
z = 'MeasuredData';
allowing me to write instead:
w{k,1}.(x).(y).(z)(1,len).(y)
using the dot notation.
My goal/question: I want to load the values stored in a .mat file from the original .tdms files in a loop to a cell array (or if I can do better than a cell array: please tell me), do the necessary calculations, and then save each 'corrected' .mat file using the original name.
So far, I have gotten a multitude of errors from trying a variety of solutions, going from "getfieldnames", trying to pass the name of the (dynamically changing) variable(s), etc.
Similar questions which have helped me get in the right direction include Saving matlab files with a name having a variable input, Dynamically Assign Variables in Matlab and http://www.mathworks.com/matlabcentral/answers/4042-load-files-containing-part-of-a-string-in-the-file-name-and-the-load-that-file , yet the result is that I am still no closer than doing manual labour in this case.
Any help would be appreciated.
If I understand your ultimate goal correctly, I think you're pretty much there. I think you're trying to process your .mat files and that the loading of all of the files into a cell array is not a requirement, but just part of your solution? Assuming this is the case, you could just load the data from one file, process it, save it and then repeat. This way you only ever have one file loaded at a time and shouldn't hit any limits.
Edit
You could certainly make a function out of your code and then call that in a loop, passing in the file name to modify. Personally I'd probably do that as I think it's neater solution. If you don't want to do that though, you could just replace w{k,1} with w then each time you load a file w would be overwritten. If you wanted to explicitly clear variables you can use the clear command with a space separated list of variables e.g. clear w len pos, but I don't think that this is necessary.
I am trying to create a schedule task that reads in a excel file and saves the data. It's working, but when I try to save new data with the same variable name, it overwrites even when I use the '-append' function.
read_date = (datestr(busdate(today)-4,'mmddyyyy'));
cd('C:\Users\jdoe\Desktop\weathertemps');
csvdata = xlsread(strcat('temp_', num2str(read_date),'.XLS'));
htemp = [csvdata(1,5),csvdata(2,5),csvdata(3,5),csvdata(4,5)];
ltemp = [csvdata(7,5),csvdata(8,5),csvdata(9,5),csvdata(10,5)];
todaydata = [str2num(read_date),htemp,ltemp];
cd('C:\Users\jdoe\Desktop\weathertemps\Data');
save mydata.mat todaydata -append;
This saves a vector<1,9> called todaydata in a mat file called mydata.mat. How do I go back into that same vector and make it an array of <2,9> with next day's data?
Append is for adding new variables to the mat file. To do what you want to do, you must load the variable from the mat file, modify it, and save it back in, overwriting the variable in the mat file.
I am working on a GUI and I have a file named 'work.mid'. The user can make some modifications to it and when they click the save button I want it to be saved as 'work1.mid' to 'c:\saved_datas\'. When they click that button second time, it should save it as 'work2.mid', on the third time 'work3.mid' and so on. Here's the code I have so far:
nmat = readmidi_java('work.mid');
Name = fullfile('c:\saved_datas\', '?????');
writemidi_java(nmat, Name);
Figuring out what should go at ????? is where I'm stuck.
The following code would work if you have no prior work*.mid or if you have any number of sequential work*.mid files inside c:\saved_datas\. Now, if the files are not in sequence, this code could be tweaked for that, just let me know if you would like to handle that case too.
Code listed here -
%// Parameters
org_filename = 'work.mid';
main_dir = 'c:\saved_datas\'; %//'
%// Your code
nmat = readmidi_java(org_filename);
%// Added code
[~,filename_noext,ext] = fileparts(org_filename)
filenames = ls(strcat(main_dir,filename_noext,'*',ext))
new_filename = strcat(filename_noext,num2str(size(filenames,1)+1),ext)
Name = fullfile(main_dir,new_filename)
%// Your code
writemidi_java(nmat, Name);
For achieving uniqueness of filenames, some also use timestamps. This could be implemented like this -
org_filename = 'work.mid'; %//'
main_dir = 'c:\saved_datas\'; %//'
[~,filename_noext,ext] = fileparts(org_filename)
new_filename = strcat('filename_noext','-',datestr(clock,'yyyy-mm-dd-hh-MM-SS'),ext)
Name = fullfile(main_dir,new_filename);
This could be done a couple of ways depending on how you have structured your GUI. You need to keep track of how many times the button has been pressed. In the callback for the button you could use a persistent variable ('count') and increment it by one at the start of the function. Then construct the filename with filename = ['work' num2str(count) '.mid']. Alternatively you could increment a class member variable if you have implemented your GUI using OOP.
To save the file use the 'save()' function with the previously constructed file name and a reference to the variable.
Check out the documentation for persistent variables, save, fullfile and uiputfile for extra info.