How to resolve the algorithm Compare a list of strings step by step in the Ruby programming language

Published on 12 May 2024 09:40 PM
#Ruby

How to resolve the algorithm Compare a list of strings step by step in the Ruby programming language

Table of Contents

Problem Statement

Given a   list   of arbitrarily many strings, show how to:

Each of those two tests should result in a single true or false value, which could be used as the condition of an   if   statement or similar. If the input list has less than two elements, the tests should always return true. There is no need to provide a complete program and output. Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name   strings,   and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs),   with as little distractions as possible. Try to write your solution in a way that does not modify the original list,   but if it does then please add a note to make that clear to readers. If you need further guidance/clarification,   see #Perl and #Python for solutions that use implicit short-circuiting loops,   and #Raku for a solution that gets away with simply using a built-in language feature.

Let's start with the solution:

Step by Step solution about How to resolve the algorithm Compare a list of strings step by step in the Ruby programming language

Option 1:

  • uniq: Returns a new array with duplicate values removed.
  • one?: Checks if all elements in an array are the same, returning true if they are and false otherwise.
  • ==: Checks if two arrays are equal, returning true if they are and false otherwise.
  • sort: Returns a new array with the elements sorted in ascending order.

So, strings.uniq.one? checks if all elements in strings are the same, returning true if they are. If this is true, then strings == strings.uniq.sort also returns true because both arrays are the same (since all elements are equal).

Option 2:

  • all?: Checks if a block evaluates to true for all elements in an array, returning true if it does and false otherwise.
  • first: Returns the first element in an array.
  • each_cons(2): Returns an enumerator that yields pairs of consecutive elements in an array.
  • <: Checks if one element is less than another.

So, strings.all?{|str| str == strings.first} checks if all elements in strings are equal to the first element, returning true if they are. If this is true, then strings.each_cons(2).all?{|str1, str2| str1 < str2} also returns true because the elements are all in ascending order.

Source code in the ruby programming language

strings.uniq.one?                 # all equal?
strings == strings.uniq.sort      # ascending?


strings.all?{|str| str == strings.first} # all equal?
strings.each_cons(2).all?{|str1, str2| str1 < str2} # ascending?

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