Replacing values in array with values from another array

The values in each row of an array correspond to the values i, j of an upper triangular array. How do I return a vector with elements that are the corresponding i, j value in the array? For example:

test_array = [1 2; 2 3; 1 3];
test_upper_triangular_array = [0.5 0.25 0.7; 0 0.8 0.6; 0 0 1.1];
desired_vector = [0.25 0.6 0.7]

Answer 1

[Star Strider]

Try this —

test_array = [1 2; 2 3; 1 3];
test_upper_triangular_array = [0.5 0.25 0.7; 0 0.8 0.6; 0 0 1.1]

test_upper_triangular_array = 3×3

0.5000 0.2500 0.7000 0 0.8000 0.6000 0 0 1.1000

lidx = sub2ind(size(test_upper_triangular_array), test_array(:,1), test_array(:,2)) % Convert Subscripts To Linear Indices

lidx = 3×1

4 8 7

result = test_upper_triangular_array(lidx)

result = 3×1

0.2500 0.6000 0.7000

% desired_vector = [0.25 0.6 0.7]

EDIT —

Transpose to get row vector:

result_row = result.'

result_row = 1×3

0.2500 0.6000 0.7000

.

[KALYAN ACHARJYA]

+1 @Star Strider Quick way

@L'O.G. Other ways: Using Loop

[L'O.G.]

@Star Strider Thank you!

[Star Strider]

As always, my pleasure!