isbn-verifier
This commit is contained in:
parent
1224cca405
commit
0c3373b87e
|
@ -0,0 +1,27 @@
|
|||
{
|
||||
"authors": [
|
||||
"stfnsr"
|
||||
],
|
||||
"contributors": [
|
||||
"angelikatyborska",
|
||||
"Cohen-Carlisle",
|
||||
"devonestes",
|
||||
"herminiotorres",
|
||||
"neenjaw",
|
||||
"sotojuan"
|
||||
],
|
||||
"files": {
|
||||
"solution": [
|
||||
"lib/isbn_verifier.ex"
|
||||
],
|
||||
"test": [
|
||||
"test/isbn_verifier_test.exs"
|
||||
],
|
||||
"example": [
|
||||
".meta/example.ex"
|
||||
]
|
||||
},
|
||||
"blurb": "Check if a given string is a valid ISBN-10 number.",
|
||||
"source": "Converting a string into a number and some basic processing utilizing a relatable real world example.",
|
||||
"source_url": "https://en.wikipedia.org/wiki/International_Standard_Book_Number#ISBN-10_check_digit_calculation"
|
||||
}
|
|
@ -0,0 +1 @@
|
|||
{"track":"elixir","exercise":"isbn-verifier","id":"6c4a3518e48f4c1595cc3d84835d58f8","url":"https://exercism.org/tracks/elixir/exercises/isbn-verifier","handle":"negrienko","is_requester":true,"auto_approve":false}
|
|
@ -0,0 +1,4 @@
|
|||
# Used by "mix format"
|
||||
[
|
||||
inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
|
||||
]
|
|
@ -0,0 +1,24 @@
|
|||
# The directory Mix will write compiled artifacts to.
|
||||
/_build/
|
||||
|
||||
# If you run "mix test --cover", coverage assets end up here.
|
||||
/cover/
|
||||
|
||||
# The directory Mix downloads your dependencies sources to.
|
||||
/deps/
|
||||
|
||||
# Where third-party dependencies like ExDoc output generated docs.
|
||||
/doc/
|
||||
|
||||
# Ignore .fetch files in case you like to edit your project deps locally.
|
||||
/.fetch
|
||||
|
||||
# If the VM crashes, it generates a dump, let's ignore it too.
|
||||
erl_crash.dump
|
||||
|
||||
# Also ignore archive artifacts (built via "mix archive.build").
|
||||
*.ez
|
||||
|
||||
# Ignore package tarball (built via "mix hex.build").
|
||||
isbn_verifier-*.tar
|
||||
|
|
@ -0,0 +1,75 @@
|
|||
# Help
|
||||
|
||||
## Running the tests
|
||||
|
||||
From the terminal, change to the base directory of the exercise then execute the tests with:
|
||||
|
||||
```bash
|
||||
$ mix test
|
||||
```
|
||||
|
||||
This will execute the test file found in the `test` subfolder -- a file ending in `_test.exs`
|
||||
|
||||
Documentation:
|
||||
|
||||
* [`mix test` - Elixir's test execution tool](https://hexdocs.pm/mix/Mix.Tasks.Test.html)
|
||||
* [`ExUnit` - Elixir's unit test library](https://hexdocs.pm/ex_unit/ExUnit.html)
|
||||
|
||||
## Pending tests
|
||||
|
||||
In test suites of practice exercises, all but the first test have been tagged to be skipped.
|
||||
|
||||
Once you get a test passing, you can unskip the next one by commenting out the relevant `@tag :pending` with a `#` symbol.
|
||||
|
||||
For example:
|
||||
|
||||
```elixir
|
||||
# @tag :pending
|
||||
test "shouting" do
|
||||
assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"
|
||||
end
|
||||
```
|
||||
|
||||
If you wish to run all tests at once, you can include all skipped test by using the `--include` flag on the `mix test` command:
|
||||
|
||||
```bash
|
||||
$ mix test --include pending
|
||||
```
|
||||
|
||||
Or, you can enable all the tests by commenting out the `ExUnit.configure` line in the file `test/test_helper.exs`.
|
||||
|
||||
```elixir
|
||||
# ExUnit.configure(exclude: :pending, trace: true)
|
||||
```
|
||||
|
||||
## Useful `mix test` options
|
||||
|
||||
* `test/<FILE>.exs:LINENUM` - runs only a single test, the test from `<FILE>.exs` whose definition is on line `LINENUM`
|
||||
* `--failed` - runs only tests that failed the last time they ran
|
||||
* `--max-failures` - the suite stops evaluating tests when this number of test failures
|
||||
is reached
|
||||
* `--seed 0` - disables randomization so the tests in a single file will always be ran
|
||||
in the same order they were defined in
|
||||
|
||||
## Submitting your solution
|
||||
|
||||
You can submit your solution using the `exercism submit lib/isbn_verifier.ex` command.
|
||||
This command will upload your solution to the Exercism website and print the solution page's URL.
|
||||
|
||||
It's possible to submit an incomplete solution which allows you to:
|
||||
|
||||
- See how others have completed the exercise
|
||||
- Request help from a mentor
|
||||
|
||||
## Need to get help?
|
||||
|
||||
If you'd like help solving the exercise, check the following pages:
|
||||
|
||||
- The [Elixir track's documentation](https://exercism.org/docs/tracks/elixir)
|
||||
- The [Elixir track's programming category on the forum](https://forum.exercism.org/c/programming/elixir)
|
||||
- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
|
||||
- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
|
||||
|
||||
Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
|
||||
|
||||
If you're stuck on something, it may help to look at some of the [available resources](https://exercism.org/docs/tracks/elixir/resources) out there where answers might be found.
|
|
@ -0,0 +1,66 @@
|
|||
# ISBN Verifier
|
||||
|
||||
Welcome to ISBN Verifier on Exercism's Elixir Track.
|
||||
If you need help running the tests or submitting your code, check out `HELP.md`.
|
||||
|
||||
## Instructions
|
||||
|
||||
The [ISBN-10 verification process][isbn-verification] is used to validate book identification numbers.
|
||||
These normally contain dashes and look like: `3-598-21508-8`
|
||||
|
||||
## ISBN
|
||||
|
||||
The ISBN-10 format is 9 digits (0 to 9) plus one check character (either a digit or an X only).
|
||||
In the case the check character is an X, this represents the value '10'.
|
||||
These may be communicated with or without hyphens, and can be checked for their validity by the following formula:
|
||||
|
||||
```text
|
||||
(d₁ * 10 + d₂ * 9 + d₃ * 8 + d₄ * 7 + d₅ * 6 + d₆ * 5 + d₇ * 4 + d₈ * 3 + d₉ * 2 + d₁₀ * 1) mod 11 == 0
|
||||
```
|
||||
|
||||
If the result is 0, then it is a valid ISBN-10, otherwise it is invalid.
|
||||
|
||||
## Example
|
||||
|
||||
Let's take the ISBN-10 `3-598-21508-8`.
|
||||
We plug it in to the formula, and get:
|
||||
|
||||
```text
|
||||
(3 * 10 + 5 * 9 + 9 * 8 + 8 * 7 + 2 * 6 + 1 * 5 + 5 * 4 + 0 * 3 + 8 * 2 + 8 * 1) mod 11 == 0
|
||||
```
|
||||
|
||||
Since the result is 0, this proves that our ISBN is valid.
|
||||
|
||||
## Task
|
||||
|
||||
Given a string the program should check if the provided string is a valid ISBN-10.
|
||||
Putting this into place requires some thinking about preprocessing/parsing of the string prior to calculating the check digit for the ISBN.
|
||||
|
||||
The program should be able to verify ISBN-10 both with and without separating dashes.
|
||||
|
||||
## Caveats
|
||||
|
||||
Converting from strings to numbers can be tricky in certain languages.
|
||||
Now, it's even trickier since the check digit of an ISBN-10 may be 'X' (representing '10').
|
||||
For instance `3-598-21507-X` is a valid ISBN-10.
|
||||
|
||||
[isbn-verification]: https://en.wikipedia.org/wiki/International_Standard_Book_Number
|
||||
|
||||
## Source
|
||||
|
||||
### Created by
|
||||
|
||||
- @stfnsr
|
||||
|
||||
### Contributed to by
|
||||
|
||||
- @angelikatyborska
|
||||
- @Cohen-Carlisle
|
||||
- @devonestes
|
||||
- @herminiotorres
|
||||
- @neenjaw
|
||||
- @sotojuan
|
||||
|
||||
### Based on
|
||||
|
||||
Converting a string into a number and some basic processing utilizing a relatable real world example. - https://en.wikipedia.org/wiki/International_Standard_Book_Number#ISBN-10_check_digit_calculation
|
|
@ -0,0 +1,41 @@
|
|||
defmodule IsbnVerifier do
|
||||
@doc """
|
||||
Checks if a string is a valid ISBN-10 identifier
|
||||
|
||||
## Examples
|
||||
|
||||
iex> IsbnVerifier.isbn?("3-598-21507-X")
|
||||
true
|
||||
|
||||
iex> IsbnVerifier.isbn?("3-598-2K507-0")
|
||||
false
|
||||
|
||||
"""
|
||||
|
||||
@regex ~r/^(?<digits>\d{9})(?<check_digit>[0-9X])$/
|
||||
|
||||
@spec isbn?(String.t()) :: boolean
|
||||
def isbn?(isbn) do
|
||||
with isbn_without_dashes <- String.replace(isbn, "-", ""),
|
||||
%{"digits" => digits, "check_digit" => check_digit} <-
|
||||
Regex.named_captures(@regex, isbn_without_dashes) do
|
||||
rem(check_sum(digits) + check_digit(check_digit), 11) == 0
|
||||
else
|
||||
_ -> false
|
||||
end
|
||||
end
|
||||
|
||||
defp check_sum(digits) do
|
||||
{1, check_sum} =
|
||||
digits
|
||||
|> String.graphemes()
|
||||
|> Enum.reduce({10, 0}, fn digit, {index, acc} ->
|
||||
{index - 1, acc + String.to_integer(digit) * index}
|
||||
end)
|
||||
|
||||
check_sum
|
||||
end
|
||||
|
||||
defp check_digit("X"), do: 10
|
||||
defp check_digit(string), do: String.to_integer(string)
|
||||
end
|
|
@ -0,0 +1,28 @@
|
|||
defmodule IsbnVerifier.MixProject do
|
||||
use Mix.Project
|
||||
|
||||
def project do
|
||||
[
|
||||
app: :isbn_verifier,
|
||||
version: "0.1.0",
|
||||
# elixir: "~> 1.8",
|
||||
start_permanent: Mix.env() == :prod,
|
||||
deps: deps()
|
||||
]
|
||||
end
|
||||
|
||||
# Run "mix help compile.app" to learn about applications.
|
||||
def application do
|
||||
[
|
||||
extra_applications: [:logger]
|
||||
]
|
||||
end
|
||||
|
||||
# Run "mix help deps" to learn about dependencies.
|
||||
defp deps do
|
||||
[
|
||||
# {:dep_from_hexpm, "~> 0.3.0"},
|
||||
# {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
|
||||
]
|
||||
end
|
||||
end
|
|
@ -0,0 +1,130 @@
|
|||
defmodule IsbnVerifierTest do
|
||||
use ExUnit.Case
|
||||
|
||||
test "valid isbn number" do
|
||||
assert IsbnVerifier.isbn?("3-598-21508-8")
|
||||
end
|
||||
|
||||
test "invalid isbn check digit" do
|
||||
refute IsbnVerifier.isbn?("3-598-21508-9")
|
||||
end
|
||||
|
||||
test "valid isbn number with a check digit of 10" do
|
||||
assert IsbnVerifier.isbn?("3-598-21507-X")
|
||||
end
|
||||
|
||||
test "check digit is a character other than X" do
|
||||
refute IsbnVerifier.isbn?("3-598-21507-A")
|
||||
end
|
||||
|
||||
test "check digit in isbn is not treated as zero" do
|
||||
refute IsbnVerifier.isbn?("4-598-21507-B")
|
||||
end
|
||||
|
||||
test "invalid character in isbn" do
|
||||
refute IsbnVerifier.isbn?("3-598-P1581-X")
|
||||
end
|
||||
|
||||
test "X is only valid as a check digit" do
|
||||
refute IsbnVerifier.isbn?("3-598-2X507-9")
|
||||
end
|
||||
|
||||
test "valid isbn without separating dashes" do
|
||||
assert IsbnVerifier.isbn?("3598215088")
|
||||
end
|
||||
|
||||
test "isbn without separating dashes and X as check digit" do
|
||||
assert IsbnVerifier.isbn?("359821507X")
|
||||
end
|
||||
|
||||
test "isbn without check digit and dashes" do
|
||||
refute IsbnVerifier.isbn?("359821507")
|
||||
end
|
||||
|
||||
test "too long isbn and no dashes" do
|
||||
refute IsbnVerifier.isbn?("3598215078X")
|
||||
end
|
||||
|
||||
test "too short isbn" do
|
||||
refute IsbnVerifier.isbn?("00")
|
||||
end
|
||||
|
||||
test "isbn without check digit" do
|
||||
refute IsbnVerifier.isbn?("3-598-21507")
|
||||
end
|
||||
|
||||
test "too long isbn" do
|
||||
refute IsbnVerifier.isbn?("3-598-21507-XA")
|
||||
end
|
||||
|
||||
test "check digit of X should not be used for 0" do
|
||||
refute IsbnVerifier.isbn?("3-598-21515-X")
|
||||
end
|
||||
|
||||
test "input is 9 characters" do
|
||||
refute IsbnVerifier.isbn?("134456729")
|
||||
end
|
||||
|
||||
test "invalid characters are not ignored" do
|
||||
refute IsbnVerifier.isbn?("3132P34035")
|
||||
end
|
||||
|
||||
test "invalid characters are not ignored before checking length" do
|
||||
refute IsbnVerifier.isbn?("3598P215088")
|
||||
end
|
||||
|
||||
test "input is too long but contains a valid isbn" do
|
||||
refute IsbnVerifier.isbn?("98245726788")
|
||||
end
|
||||
|
||||
# Test cases from international ISBN to test variable dash placement
|
||||
# Adapted from https://en.wikipedia.org/wiki/International_Standard_Book_Number#Registrant_element
|
||||
|
||||
test "Qatar NCCAH, Doha" do
|
||||
assert IsbnVerifier.isbn?("99921-58-10-7")
|
||||
end
|
||||
|
||||
test "Singapore World Scientific" do
|
||||
assert IsbnVerifier.isbn?("9971-5-0210-0")
|
||||
end
|
||||
|
||||
test "Greece Sigma Publications" do
|
||||
assert IsbnVerifier.isbn?("960-425-059-0")
|
||||
end
|
||||
|
||||
test "Czech Republic; Slovakia Taita Publishers" do
|
||||
assert IsbnVerifier.isbn?("80-902734-1-6")
|
||||
end
|
||||
|
||||
test "Brazil Companhia das Letras" do
|
||||
assert IsbnVerifier.isbn?("85-359-0277-5")
|
||||
end
|
||||
|
||||
test "English-speaking area Simon Wallenberg Press" do
|
||||
assert IsbnVerifier.isbn?("1-84356-028-3")
|
||||
end
|
||||
|
||||
test "English-speaking area Scribner" do
|
||||
assert IsbnVerifier.isbn?("0-684-84328-5")
|
||||
end
|
||||
|
||||
test "English-speaking area Frederick Ungar" do
|
||||
assert IsbnVerifier.isbn?("0-8044-2957-X")
|
||||
end
|
||||
|
||||
test "English-speaking area J. A. Allen & Co." do
|
||||
assert IsbnVerifier.isbn?("0-85131-041-9")
|
||||
end
|
||||
|
||||
test "English-speaking area Edupedia Publications Pvt Ltd." do
|
||||
assert IsbnVerifier.isbn?("93-86954-21-4")
|
||||
end
|
||||
|
||||
test "English-speaking area Willmann-Bell" do
|
||||
assert IsbnVerifier.isbn?("0-943396-04-2")
|
||||
end
|
||||
|
||||
test "English-speaking area KT Publishing" do
|
||||
assert IsbnVerifier.isbn?("0-9752298-0-X")
|
||||
end
|
||||
end
|
|
@ -0,0 +1,2 @@
|
|||
ExUnit.start()
|
||||
ExUnit.configure(exclude: :pending, trace: true)
|
Loading…
Reference in New Issue