how to update a specific line in a text file

Hi folks,

I am going to read a formatted text file and update ONLY a line of that which can be in middle of text file. e.g. if contents of my text file are as the following:

test1      a1     a2       a3 
test2      b1     b2       b3 
test3      c1     c2       c3

I just want to update the the second line of this text file with new values like:

test2      f1     f2       f3

without changing other two lines so that I end up with

test1      a1     a2       a3 
test2      f1     f2       f3 
test3      c1     c2       c3

Is there any way to do so?

thanks in advance, --V

Answer 1

[Yash]

read the text file and them make changes to the array and then rewrite it

[Vahid]

thanks so much! I was thinking to apply exactly same way to resolve my problem:

• first, read the data from the text file and save the data in an array
• second, changing the desired element in the array
• third, writing the updated array to the text file

It should perfectly work ;D

Answer 2

[Walter Roberson]

Please see http://www.mathworks.com/matlabcentral/answers/38300-how-to-make-a-small-change-to-a-big-text-file-efficiently