How to overwrite matrix in txt file with another matrix?

I would like to replace the matrix with the title "//Event" with the variable "Events". My initial solution was to import the txt file and make separated tables so I could overwrite them. Therefore, I tried the following solution https://nl.mathworks.com/matlabcentral/answers/784276-import-several-tables-from-one-txt-file-in-matlab?s_tid=srchtitle with the code below.

var = load(Events.mat);
str = fileread('temp.txt');
tkn = regexp(str,'^/[^\n]([^;]*)([^/]*)','lineanchors','tokens');

I would like to detect with the code above the following tables:

First table named "Title" containing the string

Network defintion and parameters

Second table named "Parameters" with header and numbers:

nrTimePeriods LengthTim LTimeStep ScaleFlow ScaleCap ScaleSpeed DemandPar %header 
            21       900        10      1.14     1.00       1.00         1 %number

Third table named "Links" with header and numbers:

linknr nettype    length nrlanes satflow   speed  type CTR  nrSG  Signal(s)  nrCL ConfLinks %header
                    (m)          (veh/hr) (km/hr) 
      1       0     653.8       5   25000      60     0 %number
      2       0     580.6       5   25000      50     0 %number
      3       0     271.7       5   25000      60     0 %number
      4       0     708.5       5   25000      50     0 %number
      5       0     496.2       5   25000      60     0 %number
      

Fourth table named "Events" with header and numbers:

begintime endtime linknr nrlanes satflow  vfree   type %header
                                   (%)      (%)
     0      18900      2150      -4    	0       100      2 %number
     0      18900      2151      -3    	0       100      2
     0      18900      2149      -3    	0       100      2
     0      18900      379      -3    	0       100      2
     0      18900      358      -3    	0       100      2
     0      18900      349      -3    	0       100      2
     0      18900      2143      -3    	0       100      2
     0      18900      2144      -3    	0       100      2

[Jan]

Please explain, why you think, that this is not matching. Share this important information with us. Otherwise it is hard to guess, what you call "better".

[Tessa van Kol]

I adjusted my post. I hope this will give a more clear understanding of what I am hoping to achieve.

Refering to your question about what I define as a "better" solution. I thought a better solution would be somthing similar as described in the following post How to change a specific line in a text file?. However, taking into account that I perhapse have to change multiple tables in the text file I think using regexp as stated in my post is a better solution to my problem.

Answer 1

[Stephen23]

Assuming that the //Events block always occurs last in the text file. Lets start by looking at the content of the two files:

type temp.txt

//Title 
Network definition and parameters 

//Parameters 
;nrTimePeriods LengthTim LTimeStep ScaleFlow ScaleCap ScaleSpeed DemandPar 
            21       900        10      1.14     1.00       1.00         1 


//Links 
;linknr nettype    length nrlanes satflow   speed  type CTR  nrSG  Signal(s)  nrCL ConfLinks 
;                    (m)          (veh/hr) (km/hr)                                           
      1       0     653.8       5   25000      60     0 
      2       0     580.6       5   25000      50     0 
      3       0     271.7       5   25000      60     0 
      4       0     708.5       5   25000      50     0 
      5       0     496.2       5   25000      60     0 

//Events 
;begintime endtime linknr nrlanes satflow  vfree   type
;                                   (%)      (%)
     0      18900      2150      -4    	0       100      2
     0      18900      2151      -3    	0       100      2
     0      18900      2149      -3    	0       100      2
     0      18900      379      -3    	0       100      2
     0      18900      358      -3    	0       100      2
     0      18900      349      -3    	0       100      2
     0      18900      2143      -3    	0       100      2
     0      18900      2144      -3    	0       100      2

S = load('Events.mat');
M = S.Events

M = 2×7

900 1500 2150 -4 0 100 2 900 1500 2151 -3 0 100 2

Now we replace the last data block with that numeric matrix:

L = readlines('temp.txt');
X = find(strncmp(L,';',1),1,'last');
[fid,msg] = fopen('temp_new.txt','wt');
assert(fid>0,msg)
fprintf(fid,'%s\n',L{1:X});
fprintf(fid,'%6g%11g%10g%8g%6g%10g%7g\n',M.');
fclose(fid);

and now lets check the content of the new file:

type temp_new.txt

//Title 
Network definition and parameters 

//Parameters 
;nrTimePeriods LengthTim LTimeStep ScaleFlow ScaleCap ScaleSpeed DemandPar 
            21       900        10      1.14     1.00       1.00         1 


//Links 
;linknr nettype    length nrlanes satflow   speed  type CTR  nrSG  Signal(s)  nrCL ConfLinks 
;                    (m)          (veh/hr) (km/hr)                                           
      1       0     653.8       5   25000      60     0 
      2       0     580.6       5   25000      50     0 
      3       0     271.7       5   25000      60     0 
      4       0     708.5       5   25000      50     0 
      5       0     496.2       5   25000      60     0 

//Events 
;begintime endtime linknr nrlanes satflow  vfree   type
;                                   (%)      (%)
   900       1500      2150      -4     0       100      2
   900       1500      2151      -3     0       100      2

[Tessa van Kol]

Thank you for your solution. I wrote the following code with your solution to overwrite multiple tables in the txt file.

clear;
clc;

dirinf = dir('*.mat');
nfiles = length(dirinf);
L = readlines('temp.txt');
for n = 1:nfiles
  infile = dirinf(n).name; % extract one file name from struct
  M{n} = importdata(infile); % load the data
  infile = infile(1:end-4);
  lstring = strlength(infile);
  X(n) = (find(strncmp(L,strcat('//',infile),lstring)))+2;
  [fid,msg] = fopen('temp_new.txt','wt');
  assert(fid>0,msg)
  fprintf(fid,'%s\n',L{1:min(X)});
  fprintf(fid,'%6g%11g%10g%8g%6g%10g%7g\n',M{n}');
end

However, the results are not stored correctly in the 'temp_new.txt' file due to the following line of code:

fprintf(fid,'%s\n',L{1:min(X)});

@Stephen23 how can I rewrite this line of code that it is stored correctly.