I want to make a script in MATLAB that saves my output data with a certain name. All information for this name is in the path from the input data, like it is shown here:
path = 'C:\projektions100\algorithm1\method_A\data1';
projection =
algorithm =
method =
data =
The script then should extract the text in the path with the keyword (f.e. method) from the adjacent backslashes so the script is more flexible in case I made a spelling mistake with some folder names.
This is what I found to extract a text between a start and a end point but I cannot simply use the backslashes since there are a few of them in the path.
How should I proceed?
You can simply use a regexp with named tokens:
>> path = 'C:\projektions100\algorithm1\method_A\data1';
>> all=regexp(path,'[^\\]+\\proje[ck]tion(?<projection>[^\\]+)\\algorithm(?<algorithm>[^\\]+)\\method(?<method>[^\\]+)\\data(?<data>.+$)','names')
all =
struct with fields:
projection: 's100'
algorithm: '1'
method: '_A'
data: '1'
The problem is on how to find the end of your keywords. Here is a bit code, which loops through the keywords and looks for them in the path (stored in p2fldr, because the variable path returns the working path in MATLAB and you overshadow it if you define it).
p2fldr = 'C:\projektions100\algorithm1\method_A\data1';
% keywords
kyWrd = {'projection','algorithm','method','data'};
Tag = cell(size(kyWrd));
for i = 1:length(kyWrd)
% get keyword
ky = kyWrd{i};
% look for it in the path
idx = strfind(p2fldr,ky);
if ~isempty(idx)
% remaining path
idx_offset = idx+strlength(ky);
prm = p2fldr(idx_offset:end);
% look for file separator '\'
idx_tmp = strfind(prm,filesep);
% if you don't find one, it is pabably the last entry, so take the
% length
if isempty(idx_tmp)
idx_tmp = length(prm)+1;
end
% this is the index where it ends
idx2 = idx_tmp(1)-1;
% assign to tag-cell
Tag{i} = prm(1:idx2);
end
end
You can build a shortcut if you know that they are always in the last 4 entries of your path, so you can use strsplit right away and index the last returned cells
str_splt = strsplit(p2fldr,filesep);
Tag = cell(size(kyWrd));
for i = 1:length(kyWrd)
% index cells
str = str_splt{end-length(kyWrd)+i};
% get keyword
ky = kyWrd{i};
Tag{i} = str(length(ky)+1:end);
end
Note that this does not care if it matches your keywords (e.g. your path says 'projektions' but I defined the keyword to be 'projection')
So I have an iterative loop that extracts data from .csv files in MATLAB's active folder and plots it. I would like to take it one step further and run the script on two folders, each with their own .csv files.
One folder is called stress and the other strain. As the name implies, they contain .csv files for stress and strain data for several samples, each of which is called E3-01, E3-02, E3-03, etc. In other words, both folders have the same number of files and the same names.
The way I see it, the process would have the following steps:
Look in the stress folder, look inside file E3-01, extract the data in the column labelled Stress
Look in the strain folder, look inside file E3-01, extract the data in the column labelled Strain
Combine the data together for sample E3-01 and plot it
Repeat steps 1-3 for all files in the folders
Like I said, I already have a script that can find the right column and extract the data. What I'm not sure about is how to tell MATLAB to alternate the folder that the script is being run on.
Instead of a script, would a function be better? Something that accepts 4 inputs: the names of the two folders and the columns to extract?
EDIT: Apologies, here's the code I have so far:
clearvars;
files = dir('*.csv');
prompt = {'Plot name:','x label:','y label:','x values:','y values:','Points to eliminate:'};
dlg_title = 'Input';
num_lines = 1;
defaultans = {'Title','x label','y label','Surface component 1.avg(epsY) [True strain]','Stress','0'};
answer = inputdlg(prompt,dlg_title,num_lines,defaultans);
name_plot = answer{1};
x_label = answer{2};
y_label = answer{3};
x_col = answer{4};
y_col = answer{5};
des_cols = {y_col,x_col};
smallest_n = 100000;
points_elim = answer{6};
avg_x_values = [];
avg_y_values = [];
for file = files'
M=xlsread(file.name);
[row,col]=size(M);
if smallest_n > row
smallest_n = row;
end
end
smallest_n=smallest_n-points_elim;
avg_x_values = zeros(smallest_n,size(files,1));
avg_y_values = zeros(smallest_n,size(files,1));
hold on;
set(groot, 'DefaultLegendInterpreter', 'none');
set(gca,'FontSize',20);
ii = 0;
for file = files'
ii = ii + 1;
[n,s,r] = xlsread(file.name);
colhdrs = s(1,:);
[row, col] = find(strcmpi(s,x_col));
x_values = n(1:end-points_elim,col);
[row, col] = find(strcmpi(s,y_col));
y_values = n(1:end-points_elim,col);
plot(x_values,y_values,'DisplayName',s{1,1});
avg_x_values(:,ii)=x_values(1:smallest_n);
avg_y_values(:,ii)=y_values(1:smallest_n);
end
ylabel({y_label});
xlabel({x_label});
title({name_plot});
colormap(gray);
hold off;
avg_x_values = mean(avg_x_values,2);
avg_y_values = mean(avg_y_values,2);
plot(avg_x_values,avg_y_values);
set(gca,'FontSize',20);
ylabel({y_label});
xlabel({x_label});
title({name_plot});
EDIT 2: #Adriaan I tried to write the following function to get a column from a file:
function [out_col] = getcolumn(col,file)
file = dir(file);
[n,s,r] = xlsread(file.name);
colhdrs = s(1,:);
[row, col] = find(strcmpi(s,col));
out_col = n(1:end,col);
end
but I get the error
Function 'subsindex' is not defined for values of class 'struct'.
Error in getcolumn (line 21)
y = x(:,n);
not sure why.
You can do both, of course, and it depends on preference mainly, provided you're the sole user of the script. If others are going to use it as well, use functions instead, as they can contain a proper help file and calling help functionname will then give you that help.
For instance:
folders1 = dir(../strain/*)
folders2 = dir(../stress/*)
for ii 1 = 1:numel(folders)
operand1 = folders1{ii};
operand2 = folders2{ii};
%... rest of script
%
% Or function:
data = YourFunction(folders1{ii},folders2{ii})
end
So all in all you can use both, although from experience I find functions easier to use in the end, as you just pass parameters and don't need to trawl through the complete code to change the parameters each run.
Additionally you can partition off small parts of your program which do a fix task. If you nest your functions, and finally call just a single function in your scripts, you don't have to look at hundreds of lines of code each time you run the script, but rather can just run a single function (which can also be inside a script or function, ad infinitum).
Finally, a function has its own scope; meaning that any variables that are in that function stay within that function unless you explicitly set them as output (apart from global variables, but those are problematic anyway). This can be a good thing, or a bad thing, depending on the rest of your code. If you function would output ~20 variables for further processing, the function probably should include more steps. It'd be a good thing if you create lots of intermediate variables (I always do), because when the function's finished running, the scope of that function will be removed from memory, saving you clear tmpVar1 tmpVar2 tmpVar3 etc every few lines in your script.
For the script the argument in favour would be that it is easier to debug; you don't need dbstop on error and can step a bit easier through the script, keeping check of all your variables. But, after the debugging has been completed, this argument becomes moot, and thus in general I'd start with writing a script, and once it performs as desired, I rework it to a function at minimal extra effort.
So have some simple collumated data in text files named like:
Hm_slit_01.txt...Hm_slit_21.txt; Hs_slit_01.txt...Hs_slit_23.txt; Sm_slit_01.txt...Sm_slit_27.txt; Ss_slit_01.txt...Ss_slit_32.txt etc...
and I need to import it as datasheets into matlab, idealy with the same name but no .txt.
So I have created a function that takes a prefix Hm, Hs ... and a final number to iterate the file naming up to. BUT it doesn't save the datasheet externally in the workplace.
Here is the code.
function [datasheet] = imp_vrad(prefix,numslits)
%[data] = imp_vrad(prefix,numslits)
% imports data with filename <prefix>_slit_<##>.txt
% to be a matlab datasheet data = <prefix>_slit_<##>
% here ## starts from '01' and goes to 'numslits'
% FILES MUST BE IN WORKING DIRECTORY!
for currslit=1:numslits
if currslit < 10
filename = [prefix '_slit_0' num2str(currslit) '.txt']; %names file
data = [prefix '_slit_0' num2str(currslit)]; %names datasheet
else
filename = [prefix '_slit_' num2str(currslit) '.txt']; %names file
data = [prefix '_slit_' num2str(currslit)]; %names datasheet
end
disp(['importing ' filename ' as ' data])
importdata(filename); %imports the data
end
end
The line in question is the last line. I have also tried data=importdata(filename); to no avail.
Thanks in advance!
I'm not sure if there's a way to change the scope of a variable in matlab. You can define them dynamically using eval, but that still won't get us past the scope problem.
You have two options: if the names mater to you, you could put the imported tables in a struct, akin to what import does; or, if you only care about the index, you could import them into an array (perhaps multidimensional).
For the former you could do something like
function [datasheet] = imp_vrad(prefix,numslits)
%[data] = imp_vrad(prefix,numslits)
% imports data with filenames <prefix>_slit_<##>.txt
% into a struct with labels <prefix>_slit_<##>
% here ## starts from '01' and goes to 'numslits'
% FILES MUST BE IN WORKING DIRECTORY!
%
datasheet = struct();
for currslit=1:numslits
dataname = sprintf('%s_slit_%02d',prefix,currslit);
filename = [dataname,'.txt'];
disp(['importing ' filename ' as ' data])
data = importdata(filename); %imports the data
datasheet.(dataname) = data;
end
end
I have a simple question but I don't know how to solve it.
I want to process all the files in a folder and I want to write the output values on a separate line on a matrix. After direct the folder and get the list of the files and their names
filePattern=fullfile( myPath,'*.txt')
I applied a 'loop'. To save the results on each line for every file, this is what I'm doing but it doesn't work (the code works with one file, not with all of them).
text= {baseFileName, result2b, result3b, result4b, result5b};
Is there something wrong?
Thanks in advance! Greetings,
Emma
PD)
myPath = 'C:\SP\';
% if ~isdir(myPath)
% errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
% uiwait(warndlg(errorMessage));
% return;
a= dir (fullfile(myPath,'*.DIM')); %
fileNames = { a.name };
filePattern=fullfile( myPath,'*.txt');
txtFiles= dir(filePattern);
for k = 1:length(txtFiles)
baseFileName=txtFiles(k).name;
fullFileName= fullfile(myPath,baseFileName);
fid=fopen(fullFileName, 'r+');
for i = 1:18
m{i} = fgetl(fid);
end
result2 = m{18};
result2b= result2([12:19]);
(...)
EDIT:
I added a screenshoot about my variables. Is it possible because of the txtFiles is wrong?
I have written a function that takes the names and values of the input variables and writes them to a file. eg.
a = 10;
b = 100;
writevars('file.txt',a,b);
gives me a file file.txt that contains:
\def\a{\num{10}}
\def\b{\num{100}}
It would now like to be able to pass on all variables that are found using the who command. Eg if who returns:
a b z
I would like to be able to use writevars as if I called writers('file.txt', a, b, z).
The main problem I have is that writevars makes use of inputname... (temporary variables won't work e.g. writevars('file.txt', 100) doesn't work since there is no name to be given in the file).
ANSWER
var_names = who;
for i = 1 : length(var_names)
evalin('caller',['writevars(''file.txt'', ' char(var_names(i)) ' )']);
end
You can use EVALIN to run who from within writevars, e.g.
function writevars(filename,varargin)
%# get a list of variable names in the calling workspace and read their values
if isempty(varargin)
listOfVars = evalin('caller','who');
values = cell(size(listOfVars));
for i=1:length(listOfVars)
values{i} = evalin('caller',listOfVars{i});
end
else
%# use inputname to read the variable names into listOfVars
end
%# --- rest of writevars is here ---
It can be used by using the return value of whos command:
function GetAllVars
a = 45;
x = 67;
ff = 156;
z = who();
for i=1:numel(z)
if ~isequal(z{i},'z')
fprintf(1,'%s = %f\n',z{i},eval(z{i}));
end
end