Writing columns of data into a text file - matlab

I'm using the following code to write the vectors sortedthresh_strain and probofdetectionanddelamprop1 into a text file. However, the text file output is as follows:
0.0030672 1.6592e-080.0033489 5.1721e-080.0034143
where 0.0033489 5.1721e-08 should be on the next line of the text file. i.e. It should be:
0.0030672 1.6592e-08
0.0033489 5.1721e-08
I am unsure of how to do this.
Edit: Using the proposed answer:
0.0049331 0.0049685 0.0049894 0.0050094 0.005156 0.0051741 0.0052139 0.0053399 0.0054486 0.0056022 7.0711e-21 3.0123e-19
The 2nd column is required to contain:
7.0711e-21
3.0123e-19
And,
dlmwrite('THRESHUNCERTAINTYFINALPLOTLSIGMA5.dat'[sortedthresh_strain,probofdetectionanddelamprop1],'delimiter', '\t');

If you have R2013b or later, see this answer. If you have an earlier version but have the statistics toolbox you can use the dataset object to do this very easily just like tables in R2013b. Using dataset:
data1 = {'a','b','c'}'
data2 = [1, 2, 3]'
ds = dataset(data1, data2)
export(ds, 'file', 'data.txt')
If you don't want the variable names in the result text file you can use 'WriteVarNames', false in your call to export.
Good luck!

I think your data is in row vectors, but should be column vectors for it to work like you want.
Just add a transpose with '.
dlmwrite('THRESHUNCERTAINTYFINALPLOTLSIGMA5.dat',[sortedthresh_strain',probofdetectionanddelamprop1'],'delimiter', '\t');

Related

dicom header personal information conversion to a .txt file

I have a series of DICOM Images which I want to anonymize, I found few Matlab codes and some programs which do the job, but none of them export a .txt file of removed personal information. I was wondering if there is a function which can also save removed personal information of a DICOM images in .txt format for features uses. Also, I am trying to create a table which shows the corresponding new images ID to their real name.(subjects real name = personal-information-removed image ID)
Any thoughts?
Thanks for considering my request!
I'm guessing you only want to output to your text file the fields that are changed by anonymization (either modified, removed, or added). First, you may want to modify some dicomanon options to reduce the number of changes, in particular passing the arguments 'WritePrivate', true to ensure private extensions are kept.
First, you can perform the anonymization, saving structures of pre- and post-anonymization metadata using dicominfo:
preAnonData = dicominfo('input_file.dcm');
dicomanon('input_file.dcm', 'output_file.dcm', 'WritePrivate', true);
postAnonData = dicominfo('output_file.dcm');
Then you can use fieldnames and setdiff to find fields that are removed or added by anonymization, and add them to the post-anonymization or pre-anonymization data, respectively, with a nan value as a place holder:
preFields = fieldnames(preAnonData);
postFields = fieldnames(postAnonData);
removedFields = setdiff(preFields, postFields);
for iField = 1:numel(removedFields)
postAnonData.(removedFields{iField}) = nan;
end
addedFields = setdiff(postFields, preFields);
for iField = 1:numel(addedFields)
preAnonData.(addedFields{iField}) = nan;
end
It will also be helpful to use orderfields so that both data structures have the same ordering for their field names:
postAnonData = orderfields(postAnonData, preAnonData);
Finally, now that each structure has the same fields in the same order we can use struct2cell to convert their field data to a cell array and use cellfun and isequal to find any fields that have been modified by the anonymization:
allFields = fieldnames(preAnonData);
preAnonCell = struct2cell(preAnonData);
postAnonCell = struct2cell(postAnonData);
index = ~cellfun(#isequal, preAnonCell, postAnonCell);
modFields = allFields(index);
Now you can create a table of the changes like so:
T = table(modFields, preAnonCell(index), postAnonCell(index), ...
'VariableNames', {'Field', 'PreAnon', 'PostAnon'});
And you could use writetable to easily output the table data to a text file:
writetable(T, 'anonymized_data.txt');
Note, however, that if any of the fields in the table contain vectors or structures of data, the formatting of your output file may look a little funky (i.e. lots of columns, most of them empty, except for those few fields).
One way to do this is to store the tags before and after anonymisation and use these to write your text file. In Matlab, dicominfo() will read the tags into a structure:
% Get tags before anonymization
tags_before = dicominfo(file_in);
% Anoymize
dicomanon(file_in, file_out); % Need to set tags values where required
% Get tags after anonymization
tags_after = dicominfo(file_out);
% Do something with the two structures
disp(['Patient ID:', tags_before.PatientID ' -> ' tags_after.PatientID]);
disp(['Date of Birth:', tags_before.PatientBirthDate ' -> ' tags_after.PatientBirthDate]);
disp(['Family Name:', tags_before.PatientName.FamilyName ' -> ' tags_after.PatientName.FamilyName]);
You can then write out the before/after fields into a text file. You'd need to modify dicomanon() to choose your own values for the removed fields, since by default they are set to empty.

Insert String in a CSV file matlab

how do I insert a string into a csv file in matlab. i used this code to write some data and create my csv file:
and here is the output of the code:
I'm trying to insert some text in the first 2 columns before the numerical data..
thanks in advance :)
There are several approaches are possible here.
Let's take a look at some of them:
If you need to add string to your csv file.
For example, I create some csv file like your:
q = [1 2 3 4 5 6 7];
csvwrite('csvlist4.csv',q,2,0);
All troubles is to add some string to csv - it's because we need to combine numeric and text data. There are no good functions for it in Matlab except low levels:
c = 'some big text';
fid = fopen('csvlist4.csv','r+');
fprintf(fid,c);
How it works: the data in csv is an array. I put data in 3rd row, so first and second is an empty but they have ','. When you use fprintf it will replace this , with your text. So if text is too long it will overwrite your data.
How to avoid this?
Easiest way - is to do it with help of xlswrite function. For your example:
txt = cell(size(Q))
txt{1} = 'this is your text'
X = [txt; num2cell(Q)]
xlswrite('new.xlsx',X)
Result:
Important moment here: number of cell for text must be the same as your data. But I filled with the text only first cell in my example.
And the one more way: read csv file, modify it's data and write to csv:
csvwrite('csvlist4.csv',a,2,0);
m = csvread('csvlist4.csv');
fid = fopen('csvlist4.csv','w');
c = 'your text'
fprintf(fid, c); fprintf(fid, '\n');
fclose(fid);
dlmwrite('csvlist4.csv', m(3:end,:), '-append');
Of course you can use cell array instead c and so on and so on.
Hope it helps!

MATLAB reading CSV file with timestamp and values

I have the following sample from a CSV file. Structure is:
Date ,Time(Hr:Min:S:mS), Value
2015:08:20,08:20:19:123 , 0.05234
2015:08:20,08:20:19:456 , 0.06234
I then would like to read this into a matrix in MATLAB.
Attempt :
Matrix = csvread('file_name.csv');
Also tried an attempt formatting the string.
fmt = %u:%u:%u %u:%u:%u:%u %f
Matrix = csvread('file_name.csv',fmt);
The problem is when the file is read the format is wrong and displays it differently.
Any help or advice given would be greatly appreciated!
EDIT
When using #Adriaan answer the result is
2015 -11 -9
8 -17 -1
So it seems that MATLAB thinks the '-' is the delimiter(separator)
Matrix = csvread('file_name.csv',1,0);
csread does not support a format specifier. Just enter the number of header rows (I took it to be one, as per example), and number of header columns, 0.
You file, however, contains non-numeric data. Thus import it with importdata:
data = importdata('file_name.csv')
This will get you a structure, data with two fields: data.data contains the numeric data, i.e. a vector containing your value. data.textdata is a cell containing the rest of the data, you need the first two column and extract the numerics from it, i.e.
for ii = 2:size(data.textdata,1)
tmp1 = data.textdata{ii,1};
Date(ii,1) = datenum(tmp1,'YYYY:MM:DD');
tmp2 = data.textdata{ii,2};
Date(ii,2) = datenum(tmp2,'HH:MM:SS:FFF');
end
Thanks to #Excaza it turns out milliseconds are supported.

tab delimited text file from matlab

The following code generates a similar dataset to what I am currently working with:
clear all
a = rand(131400,12);
DateTime=datestr(datenum('2011-01-01 00:01','yyyy-mm-dd HH:MM'):4/(60*24):...
datenum('2011-12-31 23:57','yyyy-mm-dd HH:MM'),...
'yyyy-mm-dd HH:MM');
DateTime=cellstr(DateTime);
header={'DateTime','temp1','temp2','temp4','temp7','temp10',...
'temp13','temp16','temp19','temp22','temp25','temp30','temp35'};
I'm trying to convert the outputs into one variable (called 'Data'), i.e. have header as the first row (1,:), 'DateTime' starting from row 2 (2:end,1) and running through each row, and finally having 'a' as the data (2:end,2:end) if that makes sense. So, 'DateTime' and 'header' are used as the heading for the rows and column respectively. Following this I need to save this into a tab delimited text file.
I hope I've been clear in expressing what I'm attempting.
An easy way, but might be not the fastest:
Data = [header; DateTime, num2cell(a)];
filename = 'test.txt';
dlmwrite(filename,1); %# no create text file, not Excel
xlswrite(filename,Data);
UPDATE:
It appears that xlswrite actually changes the format of DateTime values even if it writes to a text file. If the format is important here is the better and actually faster way:
filename = 'test.txt';
out = [DateTime, num2cell(a)];
out = out'; %# our cell array will be printed by columns, so we have to transpose
fid = fopen(filename,'wt');
%# printing header
fprintf(fid,'%s\t',header{1:end-1});
fprintf(fid,'%s\n',header{end});
%# printing the data
fprintf(fid,['%s\t', repmat('%f\t',1,size(a,2)-1) '%f\n'], out{:});
fclose(fid);

Create an array of strings

Is it possibe to create an array of strings in MATLAB within a for loop?
For example,
for i=1:10
Names(i)='Sample Text';
end
I don't seem to be able to do it this way.
You need to use cell-arrays:
names = cell(10,1);
for i=1:10
names{i} = ['Sample Text ' num2str(i)];
end
You can create a character array that does this via a loop:
>> for i=1:10
Names(i,:)='Sample Text';
end
>> Names
Names =
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
However, this would be better implemented using REPMAT:
>> Names = repmat('Sample Text', 10, 1)
Names =
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Sample Text
Another option:
names = repmat({'Sample Text'}, 10, 1)
New features have been added to MATLAB recently:
String arrays were introduced in R2016b (as Budo and gnovice already mentioned):
String arrays store pieces of text and provide a set of functions for
working with text as data. You can index into, reshape, and
concatenate strings arrays just as you can with arrays of any other
type.
In addition, starting in R2017a, you can create a string using double quotes "".
Therefore if your MATLAB version is >= R2017a, the following will do:
for i = 1:3
Names(i) = "Sample Text";
end
Check the output:
>> Names
Names =
1×3 string array
"Sample Text" "Sample Text" "Sample Text"
No need to deal with cell arrays anymore.
Another solution to this old question is the new container string array, introduced in Matlab 2016b. From what I read in the official Matlab docs, this container resembles a cell-array and most of the array-related functions should work out of the box. For your case, new solution would be:
a=repmat('Some text', 10, 1);
This solution resembles a Rich C's solution applied to string array.
As already mentioned by Amro, the most concise way to do this is using cell arrays. However, Budo touched on the new string class introduced in version R2016b of MATLAB. Using this new object, you can very easily create an array of strings in a loop as follows:
for i = 1:10
Names(i) = string('Sample Text');
end
one of the simplest ways to create a string matrix is as follow :
x = [ {'first string'} {'Second parameter} {'Third text'} {'Fourth component'} ]