Saving/appending output values of varying vector length generated from for loop into separate files in MATLAB

Question

I need help in iteratively saving or appending the output obtained in terms of "dist" and "P" generated through a function inside a for loop. Although, the output is displayed I am unable to save the various output values from "dist" and "P" in separate files without overwriting.

The input data is provide in two excel files

Test1.xlsx
26
50
52
56
58
59
77
78
79
80

Test2.xlsx
51
52
187
188
189
191
226
227
228
229

and the adjacency matrix I used is adj.xlsx

The matlab code I was using is as below:

adj=xlsread('adjmat.xlsx','Sheet1','A1:JO275')
SP1=xlsread('Test1.xlsx','Sheet1','A1:A10');
INHBP=xlsread('Test2.xlsx','Sheet1','A1:A10');
for i=1:length(SP1)
for j=1:length(INHBP)
[dist,P]=dijkstra(adj,SP1(i),INHBP(j))
end
end

The sample output displayed in the matlab workspace is a below:

dist =
    27
P =
    26    38    40    50    51
dist =
    27
P =
    26    38    40    50    52
dist =
    78
P =
    26    38    40    50    52    55    60    63    80    82   116   117   119   187
dist =
    88
P =
    26    38    40    50    52    55    60    63    80    82   116   117   119   187   188
dist =
    98
P =
  Columns 1 through 15
    26    38    40    50    52    55    60    63    80    82   116   117   119   187   188
  Column 16
   189
dist =
    73
P =
    26    38    40    70    71    75    76   108   111   113   136   175   178   180   191
dist =
    85
P =
    26    38    40    50    52    55    60    63    80    82   116   117   118   198   226
dist =
    44
P =
    26    38    40    50    52    55    60    63    83   227
dist =
    33
P =
    26    38    40    50    52    55    60    63   166   228

But I want the results to be save in separate files for dist and P (results are varying length of vectors), for instance

dist =
    27
    27
    78
    88
    98
    73
    85
    44
    33


P =
    26    38    40    50    51
    26    38    40    50    52
    26    38    40    50    52    55    60    63    80    82   116   117   119   187
    26    38    40    50    52    55    60    63    80    82   116   117   119   187   188
    26    38    40    50    52    55    60    63    80    82   116   117   119   187   188   189
    26    38    40    70    71    75    76   108   111   113   136   175   178   180   191
    26    38    40    50    52    55    60    63    80    82   116   117   118   198   226
    26    38    40    50    52    55    60    63    83   227
    26    38    40    50    52    55    60    63   166   228

Please help me resolve this!!

Thank in advance.

Ashalatha Sreshty Molecular Biophysics Unit Indian Institute of Science

Answer 1

One method would be to dynamically generate a formatspec for fprintf in each of your calculation iterations based on the length of your P vector.

Consider the following example:

dfID = fopen('dist.txt', 'w');  % Discards existing contents
pfID = fopen('p.txt', 'w');     % Discards existing contents

l = [4 7 2];  % Dummy variable to define length of our P output per loop iteration

for ii = 1:length(l)
    dist = ii;
    fprintf(dfID, '%u\n', dist);

    P = ones(1, l(ii));
    fprintf(pfID, strcat(strtrim(repmat('%u ', 1, length(P))), '\n'), P);
end

% Clean up
fclose(dfID);
fclose(pfID);

Which produces dist.txt :

1
2
3

Along with p.txt :

1 1 1 1
1 1 1 1 1 1 1
1 1

Answer 2

You can use fopen to create your txt object and then write in this text file with fprintf:

fid1 = fopen('dist.txt','w');
fid2 = fopen('P.txt','w');

adj=xlsread('adjmat.xlsx','Sheet1','A1:JO275')
SP1=xlsread('Test1.xlsx','Sheet1','A1:A10');
INHBP=xlsread('Test2.xlsx','Sheet1','A1:A10');
for i=1:length(SP1)
for j=1:length(INHBP)

[dist,P]=dijkstra(adj,SP1(i),INHBP(j))
    b = sprintf('%d ',P);
    fprintf(fid1,'%d\n',dist)
    fprintf(fid2,'%s\n',b)
end
end

fclose(fid1);
fclose(fid2);