want to find the particular column when the column content is given

a=[1 4 5 9 40 23 18] then if a(5) on command window then output 40 then 'what is the command to know' in which column 40 is there?

Answer 1

[Andrei Bobrov]

i1 = find(a == 40)

OR

i1 = find(abs(a - 40) < 1e3*eps)

Answer 2

[Robert Cumming]

find(a==40)