operation in matrix in matlab

if i want to know the number of times an condition is fullfilled for a matrix, how can i do so;

a=[3 4 2 5 3 5];  %defining a matrix
% now what should i write if i want to know the number of times, a matrix
% has a value greater than 4.

Answer 1

[Arif Hoq]

a=[3 4 2 5 3 5];
expected_value=a(find(a>4))

expected_value = 1×2

5 5

how_many_times= length(find(a>4))

how_many_times = 2

Or

times=length(expected_value)

times = 2

[ali hassan]

what if i want to find that which entry is greater than 4

[Walter Roberson]

where = find(a>4)

Note: @Arif Hoq could also have written

expected_value = a(a>4);

the find() is not necessary in that context.

[Arif Hoq]

to find index try with this:

[row,col]=find(a>4);

[Arif Hoq]

a=[3 4 2 5 3 5];
expected_value=a(a>4)

expected_value = 1×2

5 5

how_many_times= length(find(a>4))

how_many_times = 2

[row,col]=find(a>4)

row = 1×2

1 1

col = 1×2

4 6

Answer 2

[Stephen23]

"...i want to know the number of times, a matrix has a value greater than 4."

The efficient MATLAB approach:

a = [3,4,2,5,3,5];
nnz(a>4)

ans = 2