Lookup Table the floor value

I´m a new user of Matlab and I´m trying to get the y floor value of a table. I´ve looking for it and the interpn1 command only let you to get the nearest value not the floor.

An example is for the table:

1 10

10 30

If I ask for the value of 9, I need to get 10 (if I use interpn1 nearest I get 30).

Thanks in advance

Answer 1

[Mike Hosea]

For a table x,y with x sorted ascending, you can do a linear time lookup for the value xi in the "floor" sense via

y(find(xi>=x,1,'last'))

-- Mike

Answer 2

[the cyclist]

If A is your array, I think you want something like:

 y_floor = min(A(A>9))

Answer 3

[Andrei Bobrov]

added variant

A = randi(120,5,5)
n = 9
[~,I] = min(abs(A(:)-n));
A(I)

Answer 4

[Walter Roberson]

Use the two output form of histc() to get the bin numbers, and use the bin numbers to index the y table.

Answer 5

[Jorge]

Thank you every one.

I´m using the find command to do it and it seem to works perfect.

find (A(:,1)<=9,1,'last')