variable names

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Luc Nijs
Luc Nijs 2011-5-10
Hi there, i'm quite new to matlab and I'm trying to process some data I have in several textfiles.
These textfiles have names that are very similar.
e.g. A_P1_pitchAmplitude A_P2_pitchAmplitude A_P3_pitchAmplitude A_P4_pitchAmplitude A_P5_pitchAmplitude B_P1_pitchAmplitude B_P2_pitchAmplitude B_P3_pitchAmplitude B_P4_pitchAmplitude B_P5_pitchAmplitude C_P1_pitchAmplitude C_P2_pitchAmplitude C_P3_pitchAmplitude C_P4_pitchAmplitude C_P5_pitchAmplitude
I suppose it most be possible to make some kind of a loop in which the name of the datafile is variabale. In this way I could make my code more simple instead of having to copy-paste the same code for each file. Can somebody help me on how to do this?
This is what I want to do to the different files:
A_P1_pitchMinFile = importdata('A_P1_pitchMin.txt');
A_P1_pitchMin = A_P1_pitchMinFile(1,2); %minimale pitch
A_P1_pitchMaxFile = importdata('A_P1_pitchMax.txt');
A_P1_pitchMax = A_P1_pitchMaxFile(1,2); %maximale pitch
A_P1_pitchAmplitude = importdata('A_P1_pitchAmplitude.txt');
A_P1_pitch = A_P1_pitchAmplitude(:, 1:2);
for i = 1 : length(A_P1_pitch(:,1))
if A_P1_pitch(i,2) < A_P1_pitchMin
A_P1_pitch(i,2) = NaN;
end
if A_P1_pitch(i,2) > A_P1_pitchMax
A_P1_pitch(i,2) = NaN;
end
end
Thank you! Kind regards, Luc

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回答（3 个）

Fangjun Jiang
Fangjun Jiang 2011-5-10
To construct your file name:
for i=1:5
FileName=sprintf('A_P%d_pitchAmplitude',i);
disp(FileName);
end
  2 个评论
Luc Nijs
Luc Nijs 2011-5-10
Thank you! This works. Now I have to be able to also change the 'A' into 'B' and 'C'.
Oleg Komarov
Oleg Komarov 2011-5-10
Did you try my version?

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RoJo
RoJo 2011-5-10
Not sure this is what you mean, but as a start.
You can use dir function to read in all the files in a directory
files = dir('C:\Test'); % Or whatever is your directory with the files
You then have a struct array where you can access each filename by
for i=3:size(files, 1)
fileName = strcat('C:\Test\', files(i).name);
a = importdata(fileName);
end
  1 个评论
Luc Nijs
Luc Nijs 2011-5-10
Thank you!
This is a way to prevent that files have to be in the "current directory"? And now it just loads al the files in the directory, but what If I want to select certain files from that directory?

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Oleg Komarov
Oleg Komarov 2011-5-10
Variable parts of the name
num = '1':'5';
let = 'A':'C';
Combine the variable parts
nNum = numel(num);
nLet = numel(let);
let = repmat(let,nNum,1);
num = repmat(num,1,nLet);
Build subnames
subn = reshape(sprintf('%c_P%c_pitch',[let(:).'; num]),[],nNum*nLet).';
Process each set of three files (amplitude, min, max)
for f = 1:size(subn,1)
% Import
data.(subn(f,:)) = importdata([subn(f,:) 'Amplitude.txt']);
data.([subn(f,:) 'Min']) = importdata([subn(f,:) 'Min.txt']);
data.([subn(f,:) 'Max']) = importdata([subn(f,:) 'Max.txt']);
% Set min < MIN = NaN
idx = data.(subn(f,:))(:,2) < data.([subn(f,:) 'Min'])(1,2);
data.(subn(f,:))(idx,2) = NaN;
% Set max > MAX = NaN
idx = data.(subn(f,:))(:,2) > data.([subn(f,:) 'Max'])(1,2);
data.(subn(f,:))(idx,2) = NaN;
end
Are you sure that:
pitch(:,2) < min(1,2) --> pitch(:,2) = NaN
pitch(:,2) > min(1,2) --> pitch(:,2) = NaN
what contains the first column of pitch?
  2 个评论
Luc Nijs
Luc Nijs 2011-5-10
Thank you!
I've tried it but i get an error message, stating:
??? Error using ==> vertcat
CAT arguments dimensions are not consistent.
I'm trying to find out what I did wrong...
the first column of pitch is a timestamp. Here I don't realy need it. I just want to "clean" the dataset, in which values below the pitch minimum (lowest not an the instrument that was recorded) and above the pitch maximum (highest note played) are considered to be errors in the pitch tracking.
Oleg Komarov
Oleg Komarov 2011-5-10
Enclose the code into (commenting out with % the comments):
function foo
num = ...
...
for
...
end
end
Save the function somewhere and launch it from the cmd window:
foo
Then report the full message error (especially the line where the error occurs)

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