reading the data of a file into matlab, editing it, and saving it elsewhere

Question

I have a file called EXP1_SQ1_Template.txt. it is a simple text file, containing these 8 lines:

LOAD BOX  1 SUBJ M1_299633_D295158_JUN19@1910_Aut_ERROR2 EXPT St(m)_Se(n)_Rat1 GROUP 1 PROGRAM 1908_SIP_EPHYS_ERROR2_St3_TrainWZ_Cbi (x)
LOAD BOX  2 SUBJ M2_297928_D294277_APR19@1910_Aut_ERROR2 EXPT St(m)_Se(n)_Rat2 GROUP 2 PROGRAM 1908_SIP_EPHYS_ERROR2_St3_TrainWZ_Cbi (x)
LOAD BOX  3 SUBJ M3_299632_D295158_JUN19@1910_Aut_ERROR2 EXPT St(m)_Se(n)_Rat3 GROUP 1 PROGRAM 1908_SIP_EPHYS_ERROR2_St3_TrainWZ_Cbii (x)
LOAD BOX  4 SUBJ M4_297929_D294277_APR19@1910_Aut_ERROR2 EXPT St(m)_Se(n)_Rat4 GROUP 2 PROGRAM 1908_SIP_EPHYS_ERROR2_St3_TrainWZ_Cbii (x)
LOAD BOX  5 SUBJ F5_299621_D295158_JUN19@1910_Aut_ERROR2 EXPT St(m)_Se(n)_Rat5 GROUP 1 PROGRAM 1908_SIP_EPHYS_ERROR2_St3_TrainWZ_Cbi (x)
LOAD BOX  6 SUBJ F6_297923_D294277_APR19@1910_Aut_ERROR2 EXPT St(m)_Se(n)_Rat6 GROUP 2 PROGRAM 1908_SIP_EPHYS_ERROR2_St3_TrainWZ_Cbi (x)
LOAD BOX  7 SUBJ F7_299626_D295158_JUN19@1910_Aut_ERROR2 EXPT St(m)_Se(n)_Rat7 GROUP 1 PROGRAM 1908_SIP_EPHYS_ERROR2_St3_TrainWZ_Cbii (x)
LOAD BOX  8 SUBJ F8_297924_D294277_APR19@1910_Aut_ERROR2 EXPT St(m)_Se(n)_Rat8 GROUP 2 PROGRAM 1908_SIP_EPHYS_ERROR2_St3_TrainWZ_Cbii (x)

those letters in parentheses are variables I want a user to be able to change.

this is the code (super simple) code I wrote:

Mac_Templ = 'EXP1_SQ1_Template.txt';
Mac_Data = cell2mat(importdata(Mac_Templ));
user_input_stage = input('Enter correct Stage: ');
Stage_Correction = strrep(Mac_Data, '(m)', user_input_stage);
user_input_session = input('Enter correct Session: ');
Session_Correction = strrep(Mac_Templ, '(n)', user_input_session);
user_input_list = input('Enter correct List: ');
List_Correction = strrep(Mac_Data, '(x)', user_input_list);

I have the code run, but the variable 'Mac_Templ' only stores the string 'EXP1_SQ1_Template.txt', and each of the strrep lines only save the number input, not the file itself.

Answer 1

Keeping data in cell format typically makes things more manageable. The below code rebuilds all the command strings based on the user inputs.

Mac_Templ = 'EXP1_SQ1_Template.txt';
Mac_Data = importdata(Mac_Templ);
user_input_stage = input('Enter correct Stage: ');
user_input_session = input('Enter correct Session: ');
user_input_list = input('Enter correct List: ');

for idx=1:size(Mac_Data,1)
    Mac_Data{idx} = strrep(Mac_Data{idx}, '(m)', num2str(user_input_stage));
    Mac_Data{idx} = strrep(Mac_Data{idx}, '(n)', num2str(user_input_session));
    Mac_Data{idx} = strrep(Mac_Data{idx}, '(x)', num2str(user_input_list)); 
end

% Mac_Data now contains the modified command strings
disp('Done')
disp(Mac_Data)