How to trim a text file with start and end line numbers

Hello ,

I want to trim the data.txt file with the start and end line numbers,

for example,

start line number = 5

end line number =10

I want a new .txt file with the lines only between 5 and 10.

I have attached a model data.txt with this question. Can anyone help me ?

MATLAB R2015b

Regards,

Jaffrey Hudson

Answer 1

[Vismay Raj]

read the file using

filetext = fileread('file.txt')

split the text on newline and store the array of lines in a new variable

newstr = splitlines(filetext)

use start:end in array to display required elements

s = 5
e = 10
newArr = newstr(s:e)

[Jaffrey Hudson Immanuel Jeyakumar]

Hi

this was my code,

---------------------------------------

filetext = fileread('data.txt')

newstr = splitlines(filetext)

s = 5;

e = 10;

newArr = newstr(s:e)

------------------------------------------------------

and this is my error,

Undefined function or variable 'splitlines'.

Error in trim (line 2)

newstr = splitlines(filetext)

[Vismay Raj]

try this function

newstr = strsplit(filetext,'\n')

[Jaffrey Hudson Immanuel Jeyakumar]

Yes. The newArr,

newArr =

[1x41 char] [1x41 char] [1x41 char] [1x41 char] [1x41 char] [1x41 char]

The values are stored correctly.

What is the command to write the newArr in a new text file ?

[Vismay Raj]

follow this link https://www.mathworks.com/help/matlab/ref/fprintf.html?searchHighlight=fprintf&s_tid=doc_srchtitle

[Jaffrey Hudson Immanuel Jeyakumar]

Thank you.

I wrote like this,

fileID = fopen('exp.txt','w');

%fprintf(fileID,'%6s %12s\n','x','exp(x)');

fprintf(fileID,'%s',newArr);

fclose(fileID);

Can you pease correct my script ?

Answer 2

[Pullak Barik]

I use the code-generator from the import tool to only import the lines needed from the text file, and then copied the cropped content to a new file.

% Auto-generated by MATLAB

% Setup the Import Options
opts = delimitedTextImportOptions("NumVariables", 1);

start_line_no = 5; %Change this variable to specify the starting point
end_line_no = 10; %Change this variable to specify the ending point

% Specify range and delimiter
opts.DataLines = [start_line_no, end_line_no];
opts.Delimiter = "!";

% Specify column names and types
opts.VariableTypes = "string";
opts = setvaropts(opts, 1, "WhitespaceRule", "preserve");
opts = setvaropts(opts, 1, "EmptyFieldRule", "auto");
opts.ExtraColumnsRule = "ignore";
opts.EmptyLineRule = "read";

% Import the data
test = readtable("C:\Users\pullak\Documents\MATLAB\data.txt", opts);
%Change the path above to point to your data.txt

% Convert to output type
test = table2array(test);

% Clear temporary variables
clear opts
%% Auto-generated code ends here

path = 'crop_data.txt'; 
%This stores the cropped data in the directory of the code script file, change the path as per your will

fid = fopen(path, 'w');
fprintf(fid, '%s\n', test{:});
fclose(fid);

[Jaffrey Hudson Immanuel Jeyakumar]

Thank you for the alternative solution too.