Clean up user-entered phone numbers so that they can be sent SMS messages.
The North American Numbering Plan (NANP) is a telephone numbering system used by many countries in North America like the United States, Canada or Bermuda. All NANP-countries share the same international country code: 1.
NANP numbers are ten-digit numbers consisting of a three-digit Numbering Plan Area code, commonly known as area code, followed by a seven-digit local number. The first three digits of the local number represent the exchange code, followed by the unique four-digit number which is the subscriber number.
The format is usually represented as
(NXX)-NXX-XXXX
where N is any digit from 2 through 9 and X is any digit from 0 through 9.
Your task is to clean up differently formatted telephone numbers by removing punctuation and the country code (1) if present.
For example, the inputs
+1 (613)-995-0253613-995-02531 613 995 0253613.995.0253should all produce the output
6139950253
Note: As this exercise only deals with telephone numbers used in NANP-countries, only 1 is considered a valid country code.
To run the tests, run the command dotnet test from within the exercise directory.
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// This file was auto-generated based on version 1.6.1 of the canonical data.
module PhoneNumberTest
open FsUnit.Xunit
open Xunit
open PhoneNumber
[<Fact>]
let ``Cleans the number`` () =
let expected: Result<uint64,string> = Ok 2234567890UL
clean "(223) 456-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Cleans numbers with dots`` () =
let expected: Result<uint64,string> = Ok 2234567890UL
clean "223.456.7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Cleans numbers with multiple spaces`` () =
let expected: Result<uint64,string> = Ok 2234567890UL
clean "223 456 7890 " |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid when 9 digits`` () =
let expected: Result<uint64,string> = Error "incorrect number of digits"
clean "123456789" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid when 11 digits does not start with a 1`` () =
let expected: Result<uint64,string> = Error "11 digits must start with 1"
clean "22234567890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Valid when 11 digits and starting with 1`` () =
let expected: Result<uint64,string> = Ok 2234567890UL
clean "12234567890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Valid when 11 digits and starting with 1 even with punctuation`` () =
let expected: Result<uint64,string> = Ok 2234567890UL
clean "+1 (223) 456-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid when more than 11 digits`` () =
let expected: Result<uint64,string> = Error "more than 11 digits"
clean "321234567890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid with letters`` () =
let expected: Result<uint64,string> = Error "alphanumerics not permitted"
clean "123-abc-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid with punctuations`` () =
let expected: Result<uint64,string> = Error "punctuations not permitted"
clean "123-@:!-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid if area code starts with 0`` () =
let expected: Result<uint64,string> = Error "area code cannot start with zero"
clean "(023) 456-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid if area code starts with 1`` () =
let expected: Result<uint64,string> = Error "area code cannot start with one"
clean "(123) 456-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid if exchange code starts with 0`` () =
let expected: Result<uint64,string> = Error "exchange code cannot start with zero"
clean "(223) 056-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid if exchange code starts with 1`` () =
let expected: Result<uint64,string> = Error "exchange code cannot start with one"
clean "(223) 156-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid if area code starts with 0 on valid 11-digit number`` () =
let expected: Result<uint64,string> = Error "area code cannot start with zero"
clean "1 (023) 456-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid if area code starts with 1 on valid 11-digit number`` () =
let expected: Result<uint64,string> = Error "area code cannot start with one"
clean "1 (123) 456-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid if exchange code starts with 0 on valid 11-digit number`` () =
let expected: Result<uint64,string> = Error "exchange code cannot start with zero"
clean "1 (223) 056-7890" |> should equal expected
[<Fact(Skip = "Remove to run test")>]
let ``Invalid if exchange code starts with 1 on valid 11-digit number`` () =
let expected: Result<uint64,string> = Error "exchange code cannot start with one"
clean "1 (223) 156-7890" |> should equal expectedmodule PhoneNumber
open System
let remove subString (input: string) = input.Replace (subString, "")
let startsWith (s: string) (input: string) = input.StartsWith s
let removeLeadingPlus input = if input |> startsWith "+" then input.Substring 1 else input
let cleanUpInput =
removeLeadingPlus >> remove "(" >> remove ")" >> remove " " >> remove "-" >> remove "."
let vNoLetters input =
if String.exists Char.IsLetter input
then Error "alphanumerics not permitted" else Ok input
let vNoPunctuation input =
if String.exists Char.IsPunctuation input
then Error "punctuations not permitted" else Ok input
let vCountryCode input =
match String.length input with
| 11 when input.[0] = '1' -> Ok (input.Substring 1)
| 11 -> Error "11 digits must start with 1"
| _ -> Ok input
let vLength input =
match String.length input with
| x when x > 11 -> Error "more than 11 digits"
| x when x < 10 -> Error "incorrect number of digits"
| _ -> Ok input
let vAreaCode (input: string) =
match input.[0] with
| '0' -> Error "area code cannot start with zero"
| '1' -> Error "area code cannot start with one"
| _ -> Ok input
let vExchange (input: string) =
match input.[3] with
| '0' -> Error "exchange code cannot start with zero"
| '1' -> Error "exchange code cannot start with one"
| _ -> Ok input
let clean input : Result<uint64, string> =
input
|> cleanUpInput
|> vLength
|> Result.bind vCountryCode
|> Result.bind vNoLetters
|> Result.bind vNoPunctuation
|> Result.bind vAreaCode
|> Result.bind vExchange
|> Result.map uint64A huge amount can be learned from reading other people’s code. This is why we wanted to give exercism users the option of making their solutions public.
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Community comments
Looks nice where can I learn more about Result.bind ?
There's an excellent topic written by Scott Wlaschin . It's not related to
Result.bindfunction specifically, but to the concept of thebindfunction in general. Also, here's the book by the same author you may want to take a look at.Thank you.
It's exactly what I needed.