MATLAB: Count Peaks, csv-files

csvdata importfindpeaksMATLAB

Hey there! I'm a clueless beginner when it comes to Matlab. So if you would be so kind and answer my questions as simple as possible. I have many problems with what I want to do in Matlab:
  1. Item one Import csv-files in a loop. My idea:
    for k=1:NDatei 
    if ~exist(sprintf('20140512-0013_%03d.csv',k), 'file') 
        errordlg(['File ' num2str(k) ' does not exit'],'File Error'); 
        break ; 
    end 
    data=importdata(sprintf('20140512-0013_%03d.csv',k)) ; 
    end
Whereas my data has names like '20140512-0013_001.csv', '20140512-0013_002.csv',.. Problem is that Matlab tells me that my files don't exist. I think it's a problem with the path. Do you know why Matlab doesn't find the files although they are in a subfolder of the Matlab folder?
  1. Item two Findpeaks: I want to count the Peaks in each file with a certain threshold and minimal peak distance. Apparently Matlab has some problems with my imported files, because I get the Error
Error using findpeaks
Expected X to be one of these types:
double, single, uint8, uint16, uint32, uint64, int8, int16, int32, int64
Instead its type was char.
Error in findpeaks>parse_inputs (line 90)
validateattributes(Xin,{'numeric'},{'nonempty','real','vector'},...
Error in findpeaks (line 71)
[X,Ph,Pd,Th,Np,Str,infIdx] = parse_inputs(Xin,varargin{:});
Thank you so much for your help. I will attach the files as an example. I'm really looking forward to your answers and thoughts. Cheerio! Tanja

Best Answer

Roger mentioned addpath to solve the subdirectory problem. To read a series of files, see the FAQ
http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F
I recommend the dir solution almost always. In short for your case...
 d=dir('2014*.csv');  % get the list of .csv files beginning w/ 2014

 for i=1:length(d)    % loop over the list
   [dat,txt]=xlsread(d(i).name);   % read the ith file
   % do whatever with the data here...
   ...
end
For a single file I used one of your links to get here...
>> d=dir('2014*.csv');  % get the list of .csv files beginning w/ 2014
>> [dat,txt]=xlsread(d.name);
>> whos dat
Name          Size             Bytes  Class     Attributes
dat       25004x2             400064  double              
>> whos txt
Name      Size            Bytes  Class    Attributes
txt       2x2               276  cell               
>> txt
txt = 
  'Zeit'    'Kanal A'
  '(us)'    '(V)'    
>> dat(1:3,:)
ans =
 -3.9008    0.1575
 -3.8968    0.1969
 -3.8928    0.1575
>>
Your problems on data types will go away when you read the data as above and use the numeric data array dat (or whatever you choose as a variable name instead of dat, of course).
And, if you know the headings and don't care, just return the numeric data...
dat=xlsread(d(i).name);   % read, return numeric only
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