Comparing value in matrix in matlab

clc;
clear;
linedata = [1	1	2	2
2	2	3	1.5
3	3	4	2.2
4	4	5	6.8
5	4	6	1
6	5	7	5.1
7	6	8	2.5
8	7	9	3.3
9	8	10	2.8
10	8	11	1.4
11	10	12	3.2
12	11	13	2.7
13	12	14	1.9
14	13	15	4.5];

bdata = [1	0
2	100
3	200
4	150
5	275
6	250
7	373
8	220
9	140
10	160
11	360
12	210
13	135
14	80
15	220];
fault = 2; %fault occur at w
row = linedata(fault,2) %bus 2 and bus 3 affected
col = linedata(fault,3)
load = bdata(row,2)+bdata(col,2)
col2 = col; 
%1
row_check=find(linedata(:,2)==col) 
col2 = linedata(row_check,3)
load = load+sum(bdata(col2,2))
%2
row_check=find(linedata(:,2)==col2)
col2 = linedata(row_check,3)
load = load+sum(bdata(col2,2))
%3
    for i = 1:length(col2)
          i
          col2(i)
     row_check(i)=find(linedata(:,2)==col2(i));
     row_check(i)
     end
   col2 = linedata(row_check,3)
     load = load+sum(bdata(col2,2))
    %4
      for i = 1:length(col2)
          i
           col2(i)
        row_check(i)=find(linedata(:,2)==col2(i));
               end
     col2 = linedata(row_check,3)
       load = load+sum(bdata(col2,2))
       
% there is an error in %4  
%Unable to perform assignment because the left and right sides have a different number of elements.
%Error in test3 (line 66)
        %row_check(i)=find(linedata(:,2)==col2(i));
%this error occure because row_check(i) is trying to find the value of 7 & 8 in column 2
7
8
8
%there are 2 value 8 in this column

Can someone help me to solve this?

[Walter Roberson]

What do you want to do in that case? Store just one of them? Store the entire list? Average the values for those rows?

Question: is it ever possible that there might be no match at all?

[Chau Chin Haw]

I want to find is there any value in column 2 have the same value as col2(i) Ans: yes it is possible that there is no match at all

[Walter Roberson]

     row_check(i) = any(linedata(:,2)==col2(i));

This would be true (at least one match) or false (no match)

[Chau Chin Haw]

Hi, the any fucntion doesnt give me the right output, what i am trying to do here is finding is there is any value in column 2 is same as the value is col2(i)

%col2(i)
7
8

%column2 
7
8
8
%this caused the eorror of different element to occur

[Walter Roberson]

linedata(:,2) = [7;8;8]

linedata = 3×2

0 7 0 8 0 8

●

col2 = [7;8;9]

col2 = 3×1

7 8 9

●

for i = 1:length(col2)
    row_check(i) = any(linedata(:,2)==col2(i));
end
row_check

row_check = 1x3 logical array
   1   1   0

Looks fine to me.