join a specific column from csv 2 to csv 1

i have a folder containing 10 files, a1.csv, a2.csv ... a5.csv and b1.csv, b2.csv ... b5.csv

I am trying to create a new csv file with the columns from .csv A and the second column from .csv B

folderPath = '/Volumes/Extreme SSD/ERA5/csv/'; 


for y = 1:5
    yStr = num2str(y); 
    
        
    A = csvread([folderPath,'a',yStr,'.csv']);
    B = csvread([folderPath,'b',yStr,'.csv']);
    C = [A,B(2)];
   
    csvfilename = 'c'+string(y)+'.csv';
    csvwrite(csvfilename,C);
   
end

I keep getting the message:

Error using horzcat

Dimensions of arrays being concatenated are not consistent.

with the above, what am i doing wrong?

edit to add:

When i use

C=[A,B];

there is no error

Answer 1

[Dave B]

Assuming your CSV files are shaped appropriately, you probably want:

C = [A B(:,2)]

B(2) refers to the second element in B, B(:,2) refers to the second column in B.

[Ant376]

Perfect, thank you!