How can I extract the values ​​from Vector Double? Index exceeds the number of array elements (0). Error in test1 (line 19) ax=m(1)

I got the error message, can you please help me?

Index exceeds the number of array elements (0).

Error in test1 (line 19)

ax=m(1)

Code :

delete(instrfindall);
clear all
clc
serialPort = 'COM2';                                    

s=serial(serialPort,'BaudRate',9600); 
fopen(s);
%tic 

m=[]
while 1      
  
  x=fscanf(s) ;
  
 m=[ x];
 
  m=str2num(m)
  disp(m);
ax=m(1)
ay=m(2)
az=m(3)

end


fclose(s);

Outbut -------->

m =

[]

m =

-0.0400 0.2700 0.3900 42.8000 15.0000 -5.0000 -7.0100 1.2200

-0.0400 0.2700 0.3900 42.8000 15.0000 -5.0000 -7.0100 1.2200

ax =

-0.0400

ay =

0.2700

az =

0.3900

m =

[]

Index exceeds the number of array elements (0).

Error in test1 (line 19)

ax=m(1)

Answer 1

[Walter Roberson]

you are in a loop reading from the serial port. At some point it sends you an empty line. You should check isempty(m) before you index into m

[Yamen Madamani]

Walter Roberson thanks for your answer, i used isempty (m) after m = str2num (m). it showed logical 1. what can I do ?

best regards

[Walter Roberson]

delete(instrfindall);
clear all
clc
serialPort = 'COM2';                                    

s=serial(serialPort,'BaudRate',9600); 
fopen(s);
%tic 

m=[];
while 1      
  
  x = fscanf(s);
  m = str2num(x);
  
  if isempty(m); continue; end
  
  ax = m(1)
  ay = m(2)
  az = m(3)

end


fclose(s);

[Yamen Madamani]

Walter Roberson worked, thank you very much, you saved me