How to define a conditional subset from another set?

Question

i want to define a subset from a set such that $$\\$$ X = n for: n < a and n > b

how can i write this in correct math notation?

$$X \subseteq n |n<a \wedge n > b$$

Answer 1

Why not use words?

$n$ is in $X$ when $b < n < a$ .

If you want symbols $$ X = \{ n \in N \, | \, a < n < b \} $$

The missing context is that there's a set $N$ of numbers.