Help with the fscanf function

Hello Community,

I have been trying to figure out how I can use the fscanf functions to input data:

4 6

5.2 1.3

6.2 8.8

4.9 6.9

10.2 1.2

In this format:

A B

K1 J1

K2 J2

K3 J3

K4 J4

i.e. A = 4, B = 6, K1 = 5.2 etc..

Answer 1

[Walter Roberson]

Call fscanf() with size parameter [2, inf] and use .' to transpose the output to N x 2

S = ...
    "4 6" + newline +  ...
    "5.2 1.3" + newline + ...
    "6.2 8.8" + newline + ...
    "4.9 6.9" + newline + ...
    "10.2 1.2" 

S = 
    "4 6
     5.2 1.3
     6.2 8.8
     4.9 6.9
     10.2 1.2"

data = sscanf(S, '%f %f', [2 inf]) .'

data = 5×2

4.0000 6.0000 5.2000 1.3000 6.2000 8.8000 4.9000 6.9000 10.2000 1.2000

[AMZ]

Oh thanks Walter.

I forgot to mention the values are present in a Text file say "values.txt", How do I:

• import the values from the file?
• How do I then assign to those variables?

[Walter Roberson]

%in your real code you would use a real file name
filename = tempname() + ".txt";

%preparation -- need to write some data into the file in order
%to illustrate reading data from a file

%this section exists only for demonstration purposes.
%in your real code you would skip this section and just assign to the
%filename and then do the fopen and so on

S = ...
    "4 6" + newline +  ...
    "5.2 1.3" + newline + ...
    "6.2 8.8" + newline + ...
    "4.9 6.9" + newline + ...
    "10.2 1.2";
fid = fopen(filename, 'w');
fwrite(fid, S);
fclose(fid);

%now the actual work that you would have in your real file

fid = fopen(filename, 'r');
data = fscanf(fid, '%f %f', [2 inf]) .';
fclose(fid);

data

data = 5×2

4.0000 6.0000 5.2000 1.3000 6.2000 8.8000 4.9000 6.9000 10.2000 1.2000

and if using fscanf() is not a hard requirement being imposed by someone else, then skip the fopen() and so on, and just use

data = readmatrix(filename)

data = 5×2

4.0000 6.0000 5.2000 1.3000 6.2000 8.8000 4.9000 6.9000 10.2000 1.2000