How to replace a particular string in text file

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arun 2013-10-18

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评论： Cedric 2013-10-19

I have a problem related to efficiency, the code given below will replace the string  and  with '' an ' .' the code is working properly for small size text file ,but the main problem i am facing is that if there are approx 40,0000+ lines in text file then it is taking too much time that no one can't wait so please can anyone suggest me something different which run faster than this, Thanks in advance. 
fid  = fopen('input.txt','r');
f=fread(fid,'*char')';
fclose(fid);
f = regexprep(f,' ','');
f = regexprep(f,' ',' .');
fid  = fopen('output.txt','w');
fprintf(fid,'%s',f);
fclose(fid);

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Azzi Abdelmalek 2013-10-18

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编辑：Azzi Abdelmalek 2013-10-18

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strrep is faster then regexprep

f = strrep(f,' ','');
f = strrep(f,' ',' .');

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arun 2013-10-18

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The purpose my code is, I have text file which contain text like

 did_VBD new_JJ on_IN posted_VBN recipe_NN see_VB the_DT website_NN ._. 
 did_VBD new_JJ on_IN posted_VBN recipe_NN see_VB the_DT website_NN ._. 
 did_VBD new_JJ on_IN posted_VBN recipe_NN see_VBP website_NN the_DT ._. 
 did_VBD new_JJ on_IN posted_VBN recipe_NN see_VBP website_NN the_DT ._.

first of all i want to wrap all sentences like

  did_VBD new_JJ on_IN posted_VBN recipe_NN see_VB the_DT website_NN  
  did_VBD new_JJ on_IN posted_VBN recipe_NN see_VB the_DT website_NN  
  did_VBD new_JJ on_IN posted_VBN recipe_NN see_VBP website_NN the_DT  
  did_VBD new_JJ on_IN posted_VBN recipe_NN see_VBP website_NN the_DT

and i am using the code that is 'f = regexprep(f,'\._.','</s>');' 'f = regexprep( f, '([^\n\r]+)', '<s> $1' );'

After that i want to extract the pos

  VBD JJ IN VBN NN VB DT NN  
  VBD JJ IN VBN NN VB DT NN  
  VBD JJ IN VBN NN VBP NN DT  
  VBD JJ IN VBN NN VBP NN DT

for this i am using 'f = regexprep(f,' \w*_|\,_',' ');'

As you suggest, the code which given above

 f = ['', strrep(f, '\r\n', '\r\n'), ''] ;
gives the result as
  did_VBD new_JJ on_IN posted_VBN recipe_NN see_VB the_DT website_NN ._. 
 did_VBD new_JJ on_IN posted_VBN recipe_NN see_VB the_DT website_NN ._. 
 did_VBD new_JJ on_IN posted_VBN recipe_NN see_VBP website_NN the_DT ._. 
 did_VBD new_JJ on_IN posted_VBN recipe_NN see_VBP website_NN the_DT ._.

arun 2013-10-19

在 MATLAB Online 中打开

yes, now i am using

 f = regexp(f,'\S*_','split')
 To get the following output,
  VBD JJ IN VBN NN VB DT NN  
  VBD JJ IN VBN NN VB DT NN

These statement are much better.

Thanks for your efforts and for your valuable suggestions.

Cedric 2013-10-19

You're welcome!

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