filtering a cell array according to a matrix

Imagine these two variables 'a' and 'b'. I want to filter the matrices in cell array 'b'. The matrices in cell array 'b' have 7 columns. The rows of every number in column 5 to 7 of the matrices in cell array 'b' that match the numbers in matrix 'a' should be recorded in a new variable c with the only exception that column 5 to 7 are deleted and only column 1 to 4 are recorded. How can I put a code for this?

a=rand(18,1)
b={rand(1877958,7); rand(1251972,7)};

Answer 1

[Star Strider]

Random numbers are, well, random, so there is no match (using rand), and I can only say that this code runs. I will leave it to you to test it in your actual application:

a=rand(18,1);
b={rand(1877958,7); rand(1251972,7)};
db = cell2mat(b);                       % Double Matrices Are Easier To Work With
b57 = db(:,5:7);
Lia = ismember(b57,a);
idx = find(sum(Lia,2));                 % Row Indices Of ‘b’ Where ‘b57’ & ‘a’ Match
c = db(idx,1:4)                         % Desired Output (As I Read The Question)

[AA]

thanks, it worked. i modified it a bit

for x = 1:100
  for y =  1:61

                 Lia = ismember(dateshalf{x,y},ans);

                 idx = find(sum(Lia,2));                 % Row Indices Of ‘b’ Where ‘b57’ & ‘a’ Match

Liaa{x,y}=idx;
qq{x,y} = q{x,y}(Liaa{x,y},1:60);                         % Desired Output (As I Read The Question)

     end
  end

[Star Strider]

My pleasure!