I have a text file that contains 4*10 array. I want to read 1st column element first and store that column in say x, process it and then read 2nd column and store in same variable x. Is there any commands for that? please help?

   -1.9360   20.7501   -1.3800    0.2735   -1.9360   20.7501   -1.3800    0.2735   20.7501   -1.3800
   -2.5797   27.6486   -1.3819    0.2524   -2.5797   27.6486   -1.3819    0.2524   27.6486   -1.3819
    1.5073   28.2723   -0.0000   15.0002    1.5073   28.2723   -0.0000   15.0002   -0.0000   15.0002
   -1.9770   37.0812    0.0000   15.0009   -1.9770   37.0812    0.0000   15.0009    0.0000   15.0009

[KSSV]

As the text file is small..you can import data completely into a matrix and process it.

data = importdata('textfile.txt') ;

[Sachin Patil]

No sir, I want to process column by column not complete matrix.

[KSSV]

you may try to save your text file as .xls file or .csv file then use the xlsread() function..

Answer 1

[KSSV]

clc; clear all ;
for i = 1:10  % loop for each column 
    ColNum = i;          %colmn number 
    fmt = [ repmat('%*s ',1,ColNum-1), ' %f %*[^\n]'] ;
    fid = fopen('data.txt') ;
    data = textscan(fid, fmt) ;
    %%do what you want %%
    data{1}
    fid = fclose(fid);
end

[Sachin Patil]

Sir, What will be the modification if I want to read each row?

[Sachin Patil]

Dr. Siva Srinivas Kolukula, please help.

[Stephen23]

@Sachim Patel: this is very inefficient concept and very slow code. Reading and writing from file is a slow process. Your entire concept would be simpler and faster if you simply read the whole data into MATLAB once, and perform whatever operation you want inside MATLAB. You should also learn how to process entire matrices and arrays using MATLAB, otherwise your code will be very inefficient.

See my answer for a much more efficient solution.

Answer 2

[Stephen23]

This is a much simpler and more efficient code:

M = dlmread('test.txt');

for row = 1:size(M,1) % loop over the rows
    M(row,:)
end

for col = 1:size(M,2) % loop over the columns
    M(:,col)
end

Tested on this file:

[Sachin Patil]

thank you sir, I will try.