Error in annotation conversion

Hello, I'm trying to convert the annotations file I have to numbers and I have written the code below but for AFIB condition, I'm getting an error saying that the matrix dimensions must agree. Can anybody help me? I think it's because I don't know the manipulation of cells.I'm expecting to get an array of numbers instead of the given annotations.

clc; clear all; close all;
[T2,u2,v2] = xlsread('E:\data_Lab\MITBIH\annots\ALL_sEGS\all the annots\ONLY THE 5\INI_FIVE.xlsx');
 for i=1:length(u2)
     if u2{i}=='N'
         num_annot(i)=1;
     elseif u2{i}=='AFIB'
         num_annot(i)=7;
     elseif u2{i}=='SVTA' 
         num_annot(i)=6;
     elseif u2{i}=='BII' 
         num_annot(i)=8;
    elseif u2{i}=='A' 
         num_annot(i)=2;
     elseif u2{i}=='V' 
         num_annot(i)=3;
    elseif u2{i}=='L' 
         num_annot(i)=4;
    elseif u2{i}=='R' 
         num_annot(i)=5;
    elseif u2{i}=='F' 
         num_annot(i)=9;
      else   num_annot(i)=0;
     end
 end

Answer 1

[Walter Roberson]

You should not use == to compare character vectors. You should use strcmp instead.

[SSG_newbiecoder]

Yes now the code is running without any error. Also I had to convert it using string. Thank you so much.