How to solve this problem?

Suppose I have an array that is a large m x n matrix. For a value y, if the numbers in this matrix are less than y, then i want to replace those values with 0, otherwise they are 1. how to compute this? I have written a rudimentary code, but i need help.

df = xlsread("Book1.xlsx");
for i = 1:448 %448 = number of columns
    x = df(:,i)
    if x < 40
        x = 0
    else
        x = 1
        i = i + 1
    end
end

Answer 1

[Voss]

y = 0.3;
df = rand(3,4) % random matrix

df = 3×4

0.0521 0.9094 0.8965 0.7698 0.1742 0.3911 0.7067 0.1376 0.8626 0.0311 0.2910 0.0843

df = double(df >= y)

df = 3×4

0 1 1 1 0 1 1 0 1 0 0 0

[Voss]

Reference: https://www.mathworks.com/matlabcentral/answers/422002-how-does-logical-indexing-work#answer_339556

[Arpita]

thank you that was very helpful

[Voss]

You're welcome! Any questions, let me know. Otherwise, please "Accept" this answer. Thanks!