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sschellhoff's solution

to Pangram in the OCaml Track

Published at May 24 2019 · 0 comments
Test suite


This exercise has changed since this solution was written.

Determine if a sentence is a pangram. A pangram (Greek: παν γράμμα, pan gramma, "every letter") is a sentence using every letter of the alphabet at least once. The best known English pangram is:

The quick brown fox jumps over the lazy dog.

The alphabet used consists of ASCII letters a to z, inclusive, and is case insensitive. Input will not contain non-ASCII symbols.

Getting Started

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To work on the exercises, you will need Opam and Base. Consult opam website for instructions on how to install opam for your OS. Once opam is installed open a terminal window and run the following command to install base:

opam install base

To run the tests you will need OUnit. Install it using opam:

opam install ounit

Running Tests

A Makefile is provided with a default target to compile your solution and run the tests. At the command line, type:


Interactive Shell

utop is a command line program which allows you to run Ocaml code interactively. The easiest way to install it is via opam:

opam install utop

Consult utop for more detail.

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Wikipedia https://en.wikipedia.org/wiki/Pangram

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.


open OUnit2
open Pangram

let ae exp got _test_ctxt = assert_equal ~printer:string_of_bool exp got

let tests = [
   "sentence empty" >::
      ae false (is_pangram "");
   "recognizes a perfect lower case pangram" >::
      ae true (is_pangram "abcdefghijklmnopqrstuvwxyz");
   "pangram with only lower case" >::
      ae true (is_pangram "the quick brown fox jumps over the lazy dog");
   "missing character 'x'" >::
      ae false (is_pangram "a quick movement of the enemy will jeopardize five gunboats");
   "another missing character, e.g. 'h'" >::
      ae false (is_pangram "five boxing wizards jump quickly at it");
   "pangram with underscores" >::
      ae true (is_pangram "the_quick_brown_fox_jumps_over_the_lazy_dog");
   "pangram with numbers" >::
      ae true (is_pangram "the 1 quick brown fox jumps over the 2 lazy dogs");
   "missing letters replaced by numbers" >::
      ae false (is_pangram "7h3 qu1ck brown fox jumps ov3r 7h3 lazy dog");
   "pangram with mixed case and punctuation" >::
      ae true (is_pangram "\"Five quacking Zephyrs jolt my wax bed.\"");
   "upper and lower case versions of the same character should not be counted separately" >::
      ae false (is_pangram "the quick brown fox jumps over with lazy FX");

let () =
  run_test_tt_main ("pangram tests" >::: tests)
let is_pangram str = 
    let lower =
        String.lowercase_ascii str
    let alphabet =
        Array.to_list (Array.make 26 'a' |> Array.mapi (fun i c -> int_of_char c + i |> char_of_int))
    let rec helper elements =
        match elements with
        | [] -> true
        | (c::cs) -> if String.contains lower c then helper cs else false
    helper alphabet

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