How to remove the string concerned from the original string

Probably something like this:

def strip_leading_number(string) when is_binary(string) do
  case Regex.run(~r/^\d+-/, string) do
    [match] -> string |> String.replace(match, "")
    _ -> string
  end
end

thank you, but that has a bug when my url is like this

125-1jump-test-for12-test-125-

it removes all 125- like this:

"1jump-test-for12-test-"

but I want this:

"1jump-test-for12-test-125-"

I thought your edit meant you wanted to remove all of them, sorry.

In that case, it’s even simpler:

def strip_leading_number(string) when is_binary(string) do
  string |> String.replace(~r/^\d+-/, "")
end

@shahryarjb you could also use:

iex> string = "125-1jump-test-for12-test-125-"
iex> Regex.replace(~r/^\d+-/, string, "")
"1jump-test-for12-test-125-"

@david_ex do you know if there are any big differences between the two functions? (will try to check the source later today)

There’s no difference: String.replace/4 proxies the call to Regex.replace/4. See code

FYI, when looking at the Elixir docs for a given function (e.g. Regex.replace/4), you can click on </> in the top right where the function head is displayed and it will take you to the relevant location in the source code.

nice! thanks for the tip!