Vectors must be same length error

I have been given this code but it skips out the first line of data, meaning I cannot plot it as the vectors are different sizes, and I don't understand why? Very limited knowledge of MATLAB, I'm just trying to get out the raw data that is used to make the graphs.

filename = sprintf('IMT1.txt', pwd, date, sample);
Th = importdata(filename);
trans = Th.data;
text = Th.textdata;
text = text(2:length(text),:);
epoch = text(:,1);

for j = 1:length(epoch)
trans_time(j) = str2num(epoch{j});
end
trans_time = trans_time.'/1e3;
figure(1)
plot(trans_time-min(trans_time), trans/max(trans))
xlabel('Time (s)')
ylabel('Normalised Intensity')

[Jan]

Please post the complete error message.

By the way, the first line is not complete:

filename = sprintf('IMT1.txt', pwd, date, sample);

You have 3 arguments, but the format string does not have any format operators. See:

sprintf('hello', 9)
sprintf('hello %d', 9)
sprintf('hello %s', 'Megan')

Answer 1

[Stephan]

Hi,

i suggest to make life easier by working with a table:

% import your txt-file as table
Th = readtable('IMT1.txt','MultipleDelimsAsOne',true,'Delimiter',...
    {' ','\t'},'ReadVariableNames',false);
% The 4.th column is only tabluator - delete it
Th.Var4 = [];
% The names may not be correct - adapt it to your needs:
Th.Properties.VariableNames = {'epoch','trans_time','intensity'}

This piece of code imports your data to a table with formats:

double, duration, double

in the order of the 3 columns and looks like:

Th =

  179×3 table

      epoch        trans_time     intensity
    __________    ____________    _________

    1.5506e+09    11:21:10.234      51029  
    1.5506e+09    11:21:17.475      50973  
    1.5506e+09    11:21:24.719      50953  
    1.5506e+09    11:21:31.961      51055  
    1.5506e+09    11:21:39.201      50989
    ... lots of lines

Advantage:

str2num and friends are not needed and all columns are of the same length of rows.

Im pretty sure this solves your problem.

To perform calculations on table entries or to plot them use the dot-notation - for example:

Th.epoch = Th.epoch / 1000
plot(Th.trans_time, Th.intensity)

If you need more assistance regarding this question comment on this answer.

Best regards

Stephan