How do i change my script to print out the second word of each even line?

fn = input( 'file name: ', 's' );
 fh = fopen( fn, 'r' );
 ln = '';
 count=1;
 while ischar( ln )
     ln = fgets( fh );
     if (ischar( ln ) && mod(count,2)==0)
         fprintf( ln );
     end
     count=count+1;
 end
 fclose( fh );

I created a script that prints out the even line of a input file but i dont know how to make it print out the second word of each even line.

Answer 1

[Adam Danz]

Instead of reading the file line by line you could read in the entire text file and then extract the 2nd word from even numbered lines of the text with just 3 lines of code.

% Read entire file as a char array
C = fileread('MyTextFile.txt'); 

% Split the char array by line and then split by word. 
% ca{j}{m} is the m_th word in the j_th line of text.  
ca = cellfun(@strsplit,strtrim(strsplit(C, newline())),'UniformOutput',false);

% get 2nd word of each even numbered line unless the line only has 1 word.
% If the line is empty, it will return an empty. 
words = cellfun(@(s)s{min(numel(s),2)},ca(2:2:end),'UniformOutput',false);
%                               [1]^   [2]^^^^^^^^
% [1] get 2nd word
% [2] isolate even-numbered lines

If you'd rather maintain your fgets method, add the two lines below to display the 2nd word of ln unless it only has 1 word in which case it displays the first word.

lnSplit = strsplit(ln); 
fprintf('%s\n',lnSplit{min(numel(lnSplit),2)})
%          ^^ Assuming you want a line break

[Davifus]

yes, I would like to mantain the fget method, but where do I put

lnSplit = strsplit(ln); 
fprintf('%s\n',lnSplit{min(numel(s),2)})

Im getting errors trying to implement it to my script. I might be putting in the wrong part.

[Adam Danz]

 while ischar( ln )
     ln = fgets( fh );
     if (ischar( ln ) && mod(count,2)==0)
         lnSplit = strsplit(ln);  % <--------------------
         fprintf('%s\n',lnSplit{min(numel(lnSplit),2)}) %<-----
     end
     count=count+1;
 end

If you continue to get an error, please provide the entire error message and the value of ln that causes the error.

[Davifus]

yeah, I have that way. but im still getting.

file name: t1.txt
Undefined function or variable 's'.

Error in q2 (line 9)
         fprintf('%s\n',lnSplit{min(numel(s),2)}) 

[Adam Danz]

Yeah, I just noticed that. Typo. I just updated the answer.

Remove 's' and replace it with lnSplit.

[Davifus]

thank you it works.

[Adam Danz]

Great! Glad I could help.