MATLAB Answers

How to read a text file line by line?

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Jetson Ronald
Jetson Ronald on 9 Apr 2013
Commented: Timothy Mathias on 22 Jul 2019
Hello
I have a complicated text file,it runs row by row, first clumn is time and the next colum is corresponding acceleration, similarily it has 5 coulns of time and fivi colums of correcpoding acceleration, e.g. is givin below. How can I read this file using a matlab script?
0000 .0495 .0042 .0386 .0085 .0263 .0127 .0262 .0169 .0153
.0211 -.0079 .0254 -.0080 .0296 -.0312 .0338 -.0312 .0380 -.0545
.0423 -.0545 .0465 -.0763 .0507 -.0764 .0549 -.0996 .0592 -.0996
.0634 -.1229
Thank You
Jetson

  1 Comment

Walter Roberson
Walter Roberson on 9 Apr 2013
The last line appears to have only one time/acceleration pair. Should that be treated specially? Or do you just want to matrix will times in one column and corresponding accelerations in the other?

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Answers (3)

Image Analyst
Image Analyst on 9 Apr 2013
Edited: Image Analyst on 9 Apr 2013
Use fgetl(). From the help:
Examples
Read and display the file fgetl.m one line at a time:
fid = fopen('fgetl.m');
tline = fgetl(fid);
while ischar(tline)
disp(tline)
tline = fgetl(fid);
end
fclose(fid);
You might also want to look at the dlmread() function.

  1 Comment

Timothy Mathias
Timothy Mathias on 22 Jul 2019
Update for Matlab R2019a
Use readmatrix() instead of dlmread()

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Ahmed A. Selman
Ahmed A. Selman on 18 Apr 2013
Try selecting one dimension a time for each line, e.g.,
...
time=fscanf(fID,'%g',[1 1:2:inf]);
acce=fscanf(fID,'%g',[1 2:2:inf]);
...

  2 Comments

Walter Roberson
Walter Roberson on 18 Apr 2013
If you read with inf as a size, then you are going to read to end of file, in which case the second fscanf() is not going to have any file to read from.
The size argument of fscanf() can be a scalar or a vector of length 2, but it cannot be a vector with more than 2 element such as [1 1:2:inf]
Jan
Jan on 18 Apr 2013
@Ahmed: Did you try the code? What do you expect as result of 1:2:inf? It must be a vector with infinite length, which must be stored in an infinitely large memory.
In addition, like Walter has explained already, fscanf reads the file sequentially, such that the idea of importing the variables one after the other does not match the was Matlab works.

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Ugur CAN KOR
Ugur CAN KOR on 14 Jan 2018
How can I read this file? matlab code?

  3 Comments

Image Analyst
Image Analyst on 14 Jan 2018
I'd use fgetl() to read a line, then use sscanf() or textscan() to parse the line.
Image Analyst
Image Analyst on 16 Jan 2018
How about this:
fullFileName = fullfile(pwd, 'canakkale.txt')
t = readtable(fullFileName)

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