How to extract data selection from multiple .txt files and plot one graph?
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Hello everyone,
I have multiple .txt files like the one (please, check the .txt file enclosed). The data of interest is these two specific columns "Zreal" and "Zimag" (it can be seen in the image below):
I've created to scripts. One named 'read_gamry_data' and the other 'nyquist_gamry'.
Here is the code 'read_gamry_data'
% EDIT: adding function call so errors are displayed here (CL)
data = read_gamry_data('Sample Potentiostatic EIS.txt')
function [data] = read_gamry_data(fname)
%READ_GAMRY_DATA Gets the data matrices in the file "fname" and
%stores them into the cell "data"
%get all lines of the file
stra = {};
fid=fopen(fname,'r');
sl = fgetl(fid);
while ischar(sl)
stra{end+1,1}=strtrim(sl);
sl = fgetl(fid);
end
fclose(fid);
%get the EIS data from the gamry .txt files
strid_dataset = 'ZCURVE';
id_start = [];
data = cell(length(id_start),1);
for y = 1:length(id_start)
for z = id_start(y):id_end(y)
if strcmp(strid_dataset,stra{z}(1:min(length(stra{z}),length(strid_dataset))))
%read data matrix
rstart = z+3;
rend = rstart;
while rend<=id_end(y) && length(split(stra{rend}))>1
rend = rend+1;
end
rend = rend-1;
break;
end
end
data{y}=zeros(rend-rstart+1,length(split(stra{rstart})));
for z = rstart:rend
data{y}(z-rstart+1,:)=(sscanf(stra{z},'%f'))';
end
end
end % added this CL
and here is the code of 'nyquist_gamry' script. Before just plotting, I need to correct the data by the area, so I tried:
clear all;close all;
dir_files = 'EIS'
area = (pi/4)*1.5^2
fname = dir(fullfile(dir_files,'*.txt'));
for a = 1:length(fname)
data{a} = read_gamry_data(strcat(dir_files,'/', fname{a}));
data{a}{1}(:,1:2) = area.*data{a}{1}(:,1:2);
plotgraph(1,data{a}{1}(:,1),-data{a}{1}(:,2))
hold on
end
xlabel('Z_{real}(\Omega.cm^2)', 'FontSize', 12)
ylabel('-Z_{imag}(\Omega.cm^2)','FontSize', 12)
set(gca,"dataaspectratio",[1,1,1])
I constantly having errors, especially saying that my index is not supported. Can anyone try to run it and see if you can help me with? I would like to hear any suggestion from you all.
Kindly
Leandro
1 个评论
Cris LaPierre
2024-4-16
编辑：Cris LaPierre
2024-4-16
I edited your code so that it could be run here. The sample file does not generate any errors, but the final result is also empty, so yout code is not properly loading the data..
Please share the full error message (all the red text).
采纳的回答
The indexing error suggests something is wrong with how your code handles multiple files. As for loading the data, if your files all share the exact same formatting, you can just use readtable.
data = readtable('Sample Potentiostatic EIS.txt','numHeaderLines',96)
plot(data.Zreal,-data.Zimag)
xlabel('Z_{real}(\Omega.cm^2)', 'FontSize', 12)
ylabel('-Z_{imag}(\Omega.cm^2)','FontSize', 12)
4 个评论
The issue is that fname is a structure, not a cell array.
Another issue is that the number format is not consistant between your files. Specifically, the decimal separator is a period in the first file you shared, but a comma in the second one. Once that is consistant, the error below goes away. Since a period is the default one, the code below shows how to use readtable to load a file with a comma as the separator.
It's a bit more, but I load the file first as text, find the ZCURVE TABLE row, then use that as an input to readtable to set the number of headerlines.
fname = dir('*.txt')
You can access the EIS folder as you currently do, but I would update the input to the read function to use fullfile based on the results of dir.
area = (pi/4)*1.5^2;
for a = 1:length(fname)
str = readlines(fullfile(fname(a).folder, fname(a).name));
idx = find(str=="ZCURVE TABLE");
data{a} = readtable(fullfile(fname(a).folder, fname(a).name),'numHeaderLines',idx,"DecimalSeparator",",");
data{a}(:,["Zreal","Zimag"]) = area.*data{a}(:,["Zreal","Zimag"]);
plot(data{a}.Zreal,-data{a}.Zimag)
hold on
end
hold off
xlabel('Z_{real}(\Omega.cm^2)', 'FontSize', 12)
ylabel('-Z_{imag}(\Omega.cm^2)','FontSize', 12)
Leandro
2024-4-17
Cris LaPierre
2024-4-17
I mean do this
fullfile(fname(a).folder, fname(a).name)
instead of this
strcat(dir_files,'/', fname{a})
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