How to convert string to Regex

Question

I have this code

reg=~r/(\d{4}.csv)/
raw="some craxy trashy text blabla 0044.csv"
Regex.scan(reg,raw, capture: :all_but_first)

This returns 0044.csv.

However, I need to load the ~r/(\d{4}.csv)/ from a database, so I will save it as

"~r/(\d{4}.csv)/"

This is a string. When I load it to a variable, it will be a string.

How can I pass it to a Regex.scan?

Answer 1

You can use Regex.compile/2 or Regex.compile!/2

iex> Regex.compile("(\\d{4}.csv)")    
{:ok, ~r/(\d{4}.csv)/}

You will need an extra backslash for escaping, otherwise you will end up with:

iex> Regex.compile("(\d{4}.csv)")    
{:ok, ~r/(\x7F{4}.csv)/}