I have a text file with several HEX values following a format like so:
%
AAAAAAAA
%
AAAAAAAB
and I am trying to use the fgetl() function in MATLAB to obtain the size of the HEX values (for a purpose of which I'm not entirely certain of... if it is important to you, I'll try to decipher what they were doing). Currently, this is what is being attempted:
folder = 'FolderA\hexdata.txt';
fidr = fopen(folder);
while ~feof(fidr)
get = fgetl(fidr);
hexdata=get;
if strncmp(get,'%',1)
time=time+.5;
continue
elseif size(get)<8
continue
end
%Do stuff here
end
For some reason, fgetl is returning -1 every time which I know means the line it is reading only contains the end-of-file marker. Is there something obvious I am doing wrong that I just don't see? I'm not the strongest MATLAB coder by any stretch of the imagination, so it is very possible I am missing something obvious.
Take a look at your filename folder, a seperator is missing. Use fullfile to get a proper path.
Related
I am working on transforming an image into a set of emojis, depending on how many colors are there. The Maths part is done. I have the matrix of numbers from 0 to 30, but I specifically need to convert the numbers into symbols and I was thinking about emojis since they are so used nowadays.
My question is how am I supposed to read a matrix of integers from a file, transform the matrix of integers into a matrix with different emojis (eventually, from a list of my choice) and put the output in another text file, this time containing the emojis? Is that possible? I guess it should be, but how do I do that? Does anyone have any suggestions?
The problem that I face is actually with the emojis unicode, I don't seem to have success when it comes to receiving messages on the console in their case. I just get "? ?" instead of a smiley face. But that thing happens only for them, the ASCII characters seem to work a bit better. The problem with ASCII characters is that I need, again, expressive images instead of numbers or random pipe shapes.
There is the code:
%make sure you have the "1234567.jpg" in the same location as the .m file
imdata = imread('1234567.jpg');
[X_no_dither,map] = rgb2ind(imdata,30,'nodither');
imshow(X_no_dither,map)
% and there I try to put the output in a text file
dlmwrite('result.txt',X_no_dither,'delimiter',"\t");
Ok, and the output in the text file is:
0 0 0 0 26 26 ... etc.
And I wonder how am I supposed to write the code in such a way that I will get emojis instead of numbers.
🤔 🤔 🤔 🤔 💖 💖 ... etc.
That's how I'd want the output to be like. But, from what I tried yesterday, I cannot print them without getting warnings/errors.
What you need to do is create a table with your 30 emojis (this documentation page might be helpful), then index into that table. I'm using the compose function as indicated in the page above, it should also be possible to copy-paste emojis into your M-file. If you don't see the emojis in MATLAB's console, change the font you're using.
For example:
table = [compose("\xD83D\xDE0E"),
"B", % find the utf16 encoding for your emojis, or copy-paste them in
"C",
"D",
...
];
output = table(X_no_dither + 1);
f = fopen('result.txt', 'wt');
for ii = 1:size(output, 1)
fprintf(f, '%s', output(ii, :));
fprintf(f, '\n');
end
fclose(f);
This will write the file out in UTF16 format, which is what MATLAB uses. If you're on Windows this might work well for you. On other platforms you might want to save as UTF8 instead, which can be accomplished by opening the file in UTF8 mode:
f = fopen('result.txt', 'wt', 'native', 'UTF-8');
Note that, even if you don't manage to get the emojis shown in the MATLAB command window, opening the text file in an editor will show the emojis correctly.
I have been trying in vain for days to do one seemingly simple thing--I want to read data from a .txt file that looks like this:
0.221351321
0.151351321
0.235165165
8.2254546 E-7
into Matlab. I've been able to load the data in the .txt file as a column vector using the fscanf command, like so:
U=fscanf(FileID, '%e')
provided that I go through the file first and remove the space before the 'E' wherever scientific notation occurs in the data set.
Since I have to generate a large number of such sets, it would be impractical to have to do a search-and-replace for every .txt file.
Is there a way for matlab to read the data as it appears, as in the above example (with the space preceding 'E'), and put it into a column vector?
For anyone who knows PARI-GP, an alternate fix would be to have the output devoid of spaces in the first place--but so far I haven't found a way to erase the space before 'E' in scientific notation, and I can't predict if a number in scientific notation will appear or not in the data set.
Thank you!
Thank you all for your help, I have found a solution. There is a way to eliminate the space from PARI-GP, so that the output .txt file has no spaces to begin with. I had the output set to "prettymatrix". One needs to enter the following:
? \o{0}
to change the output to "Raw," which eliminates the space before the "E" in scientific notation.
Thanks again for your help.
A simple way, may not be the best, is to read line by line, remove the space and convert back to floating point number.
For example,
x = []
tline = fgetl(FileID);
while ischar(tline)
x = [x str2num(tline(find(~isspace(tline))))]
tline = fgetl(FileID);
end
One liner:
data = str2double(strsplit(strrep(fileread('filename.txt'),' ',''), '\n'));
strrep removes all the spaces, strsplit takes each line as a separate string, and str2double coverts the strings to numbers.
I have a fixed width file format (original was input for a Fortran routine). Several lines of the file look like the below:
1078.0711005.481 932.978 861.159 788.103 716.076
How this actually should read:
1078.071 1005.481 932.978 861.159 788.103 716.076
I have tried various methods, textscan, fgetl, fscanf etc, however the problem I have is, as seen above, sometimes because of the fixed width of the original files there is no whitespace between some of the numbers. I cant seem to find a way to read them directly and I cant change the original format.
The best I have come up with so far is to use fgetl which reads the whole line in, then I reshape the result into an 8,6 array
A=fgetl
A=reshape(A,8,6)
which generates the following result
11
009877
703681
852186
......
049110
787507
118936
So now I have the above and thought I might be able to concatenate the rows of that array together to form each number, although that is seeming difficult as well having tried strcat, vertcat etc.
All of that seems a long way round so was hoping for some better suggestions.
Thanks.
If you can rely on three decimal numbers you can use a simple regular expression to generate the missing blanks:
s = '1078.0711005.481 932.978 861.159 788.103 716.076';
s = regexprep(s, '(\.\d\d\d)', '$1 ');
c = textscan(s, '%f');
Now c{1} contains your numbers. This will also work if s is in fact the whole file instead of one line.
You haven't mentioned which class of output you needed, but I guess you need to read doubles from the file to do some calculations. I assume you are able to read your file since you have results of reshape() function already. However, using reshape() function will not be efficient for your case since your variables are not fixed sized (i.e 1078.071 and 932.978).
If I did't misunderstand your problem:
Your data is squashed in some parts (i.e 1078.0711005.481 instead
of 1078.071 1005.481).
Fractional part of variables have 3 digits.
First of all we need to get rid of spaces from the string array:
A = A(~ismember(A,' '));
Then using the information that fractional parts are 3 digits:
iter = length(strfind(A, '.'));
for k=1:iter
[stat,ind] = ismember('.', A);
B(k)=str2double(A(1:ind+3));
A = A(ind+4:end);
end
B will be an array of doubles as a result.
kinda new to matlab here, searching the csvwrite tutorial and some of the existing webportals regarding my question couldn't find a way to pass my variables by value to the output file names while exporting in csv; providing my bellow scripts, i would like to have the output files something like output_$aa_$dd.csv which aa and dd are respectively the first and second for counters of the scripts.
for aa=1:27
for dd=1:5
M_Normal=bench(aa,dd).Y;
for j=1:300
randRand=M_Normal(randperm(12000,12000));
for jj = 1:numel(randMin(:,1)); % loops over the rand numbers
vv= randMin(jj,1); % gets the value
randMin(jj,j+1)=min(randRand(1:vv)); % get and store the min of the selction in the matix
end
end
csvwrite('/home/amir/amir_matlab/sprintf(''%d%d',aa, bb).csv',randMin);
end
end
String concatenation in MATLAB is done like a matrix concatenation. For example
a='app';
b='le';
c=[a,b] % returns 'apple'
Hence, in your problem, the full path can be formed this way.
['/home/amir/amir_matlab/',sprintf('%d_%d',aa,bb),'.csv']
Furthermore, it is usually best not to specify the file separator explicitly, so that your code can be implemented in other operating systems. I suggest you write the full path as
fullfile('home','amir','amir_matlab',sprintf('%d_%d.csv',aa,bb))
Cheers.
I've written a script that saves its output to a CSV file for later reference, but the second script for importing the data takes an ungainly amount of time to read it back in.
The data is in the following format:
Item1,val1,val2,val3
Item2,val4,val5,val6,val7
Item3,val8,val9
where the headers are on the left-most column, and the data values take up the remainder of the row. One major difficulty is that the arrays of data values can be different lengths for each test item. I'd save it as a structure, but I need to be able to edit it outside the MATLAB environment, since sometimes I have to delete rows of bad data on a computer that doesn't have MATLAB installed. So really, part one of my question is: Should I save the data in a different format?
Second part of the question:
I've tried importdata, csvread, and dlmread, but I'm not sure which is best, or if there's a better solution. Right now I'm using my own script using a loop and fgetl, which is horribly slow for large files. Any suggestions?
function [data,headers]=csvreader(filename); %V1_1
fid=fopen(filename,'r');
data={};
headers={};
count=1;
while 1
textline=fgetl(fid);
if ~ischar(textline), break, end
nextchar=textline(1);
idx=1;
while nextchar~=','
headers{count}(idx)=textline(1);
idx=idx+1;
textline(1)=[];
nextchar=textline(1);
end
textline(1)=[];
data{count}=str2num(textline);
count=count+1;
end
fclose(fid);
(I know this is probably terribly written code - I'm an engineer, not a programmer, please don't yell at me - any suggestions for improvement would be welcome, though.)
It would probably make the data easier to read if you could pad the file with NaN values when your first script creates it:
Item1,1,2,3,NaN
Item2,4,5,6,7
Item3,8,9,NaN,NaN
or you could even just print empty fields:
Item1,1,2,3,
Item2,4,5,6,7
Item3,8,9,,
Of course, in order to pad properly you would need to know what the maximum number of values across all the items is before hand. With either format above, you could then use one of the standard file reading functions, like TEXTSCAN for example:
>> fid = fopen('uneven_data.txt','rt');
>> C = textscan(fid,'%s %f %f %f %f','Delimiter',',','CollectOutput',1);
>> fclose(fid);
>> C{1}
ans =
'Item1'
'Item2'
'Item3'
>> C{2}
ans =
1 2 3 NaN %# TEXTSCAN sets empty fields to NaN anyway
4 5 6 7
8 9 NaN NaN
Instead of parsing the string textline one character at a time. You could use strtok to break the string up for example
stringParts = {};
tline = fgetl(fid);
if ~ischar(tline), break, end
i=1;
while 1
[stringParts{i},r]=strtok(tline,',');
tline=r;
i=i+1;
if isempty(r), break; end
end
% store the header
headers{count} = stringParts{1};
% convert the data into numbers
for j=2:length(stringParts)
data{count}(j-1) = str2double(stringParts{j});
end
count=count+1;
I've had the same problem with reading csv data in Matlab, and I was surprised by how little support there is for this, but then I just found the import data tool. I'm in r2015b.
On the top bar in the "Home" tab, click on "Import Data" and choose the file you'd like to read. An app window will come up like this:
Import Data tool screenshot
Under "Import Selection" you have the option to "generate function", which gives you quite a bit of customization options, including how to fill empty cells, and what you'd like the output data structure to be. Plus it's written by MathWorks, so it's probably utilizing the fastest available method to read csv files. It was almost instantaneous on my file.
Q1) If you know the max number of columns you can fill empty entries with NaN
Also, if all values are numerical, do you really need "Item#" column? If yes, you can use only "#", so all data is numerical.
Q2) The fastest way to read num. data from a file without mex-files is csvread.
I try to avoid using strings in csv files, but if I have to, I use my csv2cell function:
http://www.mathworks.com/matlabcentral/fileexchange/20135-csv2cell