the size problem during assignment of 3D-matrix - matlab

Question

There are two Questions.
---1---
I can successfully assign a smaller matrix to a bigger zero-matrix without problem, like this:
a = zeros(5,5,2);
b = [1 2 3];
a = b;
So I try to load the RawData from file to a 3D-matrix:
G = ["/Users/ripfreeworld/Documents/MATLAB/RawData/G01.txt",
"/Users/ripfreeworld/Documents/MATLAB/RawData/G02.txt",
"/Users/ripfreeworld/Documents/MATLAB/RawData/G03.txt",
"/Users/ripfreeworld/Documents/MATLAB/RawData/G04.txt"];
rawdata = zeros(1500,200,4);
for i = 1 : 4
rawdata(:,:,i) = load(G(i),'ascii');
end
It got stuck just at the first iteration, without getting any data from the load-function.
Then I commented the line with zeros(). And the first iteration succeed. What's the difference with the former simple code?
---2---
The second problem is:
Unable to perform assignment because the size of the left side is
1440-by-152 and the size of the right side is 1440-by-151.
I found that there was an extra column filled with "0". I deleted this column manually this time, but is there any way to keep the 3d form (cube matrix?) , by automatically filling the columns/rows of the smaller matrix with "0" or throwing away the data in the extra columns/rows of the bigger matrix?
Thank you!

Answer 1

Thanks Adriaan, the first question was started from a wrong test by overwriting.
For the second question I found an easy solution which is similar
p=zeros(5,10)*1/0;
for i=1:5
for m=1:10
if isprime((i-1)*10+m-1)
p(i,m)=(i-1)*10+m-1;
end
end
end
>> p
p =
NaN NaN 2 3 NaN 5 NaN 7 NaN NaN
NaN 11 NaN 13 NaN NaN NaN 17 NaN 19
NaN NaN NaN 23 NaN NaN NaN NaN NaN 29
NaN 31 NaN NaN NaN NaN NaN 37 NaN NaN
NaN 41 NaN 43 NaN NaN NaN 47 NaN NaN