I have 6 columns of double data in .dat format, but i need to import only column 1 2 4 and 5. how do i do it

How to code it. Im new to matlab

[Walter Roberson]

http://www.mathworks.co.uk/matlabcentral/answers/43073-a-guide-to-tags

Answer 1

[Walter Roberson]

There is no standard for .dat files. .dat is any data file format that the creating program wants to create. You will need to describe the format of the files for us to tell you how to load data from them at all.

It is often easiest to read all of the data and throw away the parts you do not need. However, for some text file formats, you can tell it which fields to save as it reads in the data, if you use textscan(). For binary files with strict format, memmapfile() can sometimes be used to read in only parts of the file.

[Ashwin Ronaldo]

i have written; a = import('x.dat'); it opens up as 6 columns and 1024 rows. i need to plot data of column 1,2,4,5. i want to eliminate column number 3 and 6. how should it be done. I have attached a sample of data

Answer 2

[Guillaume]

1. Use a self-describing variable name rather than a.

2. You don't need to delete anything to plot certain columns. Use simple matrix indexing to pass only the columns of interest

plot(a(:, [1 2 4 5]))  %only plots column 1 2 4 5

3. If you really want to delete columns, it's again simple matrix indexing:

a(:, [3 6]) = []      %delete columns 3 6

[Ashwin Ronaldo]

Sorry for the mistake in previous comment. I don't want it to be plotted, rather i would like to use quiver command. but i get error if i use quiver command

[Walter Roberson]

What error do you get with quiver()? Please show your line of code as well. My guess is that you need something like

quiver(a(:,1), a(:,2), a(:,4), a(:,5))