Concatenation of columns of several cell Arrays

I am trying to concatenate several columns of one cell array with several columns of another cell array.

I have A = 6xn, where n can be any number between 1&9.

I have B = 6xm,where m can be any number between 1&9

I need to create a cell array C = 6x1

For example:

A = 
472x2 double  471x2 double  488x2 double  496x2 double  494x2 double  495x2 double
472x2 double  471x2 double  488x2 double  496x2 double  494x2 double  495x2 double
472x2 double  471x2 double  488x2 double  496x2 double  494x2 double  495x2 double
472x2 double  471x2 double  488x2 double  496x2 double  494x2 double  495x2 double
472x2 double  471x2 double  488x2 double  496x2 double  494x2 double  495x2 double
472x2 double  471x2 double  488x2 double  496x2 double  494x2 double  495x2 double

B=

460x2 double  509x2 double  503x2 double  503x2 double  488x2 double  490x2 double  488x2 double  503x2 double  518x2 double
460x2 double  509x2 double  503x2 double  503x2 double  488x2 double  490x2 double  488x2 double  503x2 double  518x2 double
460x2 double  509x2 double  503x2 double  503x2 double  488x2 double  490x2 double  488x2 double  503x2 double  518x2 double
460x2 double  509x2 double  503x2 double  503x2 double  488x2 double  490x2 double  488x2 double  503x2 double  518x2 double
460x2 double  509x2 double  503x2 double  503x2 double  488x2 double  490x2 double  488x2 double  503x2 double  518x2 double
460x2 double  509x2 double  503x2 double  503x2 double  488x2 double  490x2 double  488x2 double  503x2 double  518x2 double

The result, for each row, of concatenating all columns of A and the first 4 columns of B will be:

C=
4891x2 double
4891x2 double
4891x2 double
4891x2 double
4891x2 double
4891x2 double

I can concatenate all columns of A for each row with:

for i=1:6
    C{i,1}=cat(1, A{i,:});
end

I want to avoid several for loops and the creation of intermediate variables, so I tried:

    for i=1:6
        C{i,1}=cat(1, A{i,:}, B(i,[1:num_extra_trials_w]));end

for i=1:6
    C{i,1}=cat(1, A{i,:}, cat(1,B(i,[1:num_extra_trials_w])));end

for i=1:6
    C{i,1}=cat(1, A{i,:}, {cat(1,B(i,[1:num_extra_trials_w]))});end

But none are creating a 6x1 cell array with 4891x2 double in each. What would be the proper syntax?

Thank you for your help!

[Stephen23]

The square brackets here

[1:num_extra_trials_w]

are totally superfluous: you are not concatenating anything, so why use the concatenation operator? The colon operator already produces a vector, so what does [] do? Answer: nothing. See:

https://www.mathworks.com/matlabcentral/answers/35676-why-not-use-square-brackets

Answer 1

[Stephen23]

You used the wrong brackets. You used curly braces to get the contents of the cells of A, but not with B. All you need is this:

C{i,1} = cat(1, A{i,:}, B{i,1:num_extra_trials_w});
                         ^                      ^ curly braces!

I even tried it myself with some random data:

Ar = [472,471,488,496,494,495];
Br = [460,509,503,503,488,490];
fun = @(r)rand(r,2);
A = arrayfun(fun,repmat(Ar,6,1),'uni',0);
B = arrayfun(fun,repmat(Br,6,1),'uni',0);
C = cell(6,1);
for k = 1:6
    C{k,1} = cat(1, A{k,:}, B{k,1:4});
end
cellfun('size',C,1)

which shows the number of rows of the arrays in C:

ans =
 4891
 4891
 4891
 4891
 4891
 4891

[ErikaZ]

Thank you, I forgot to reply.