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Posted on Aug 6, 2019

Daily Challenge #34 - WeIrD StRiNg CaSe

#challenge

The goal of this challenge is to write a function that accepts a string and returns the same string with all even indexed characters uppercased and all odd indexed characters lowercased.

This indexing should be zero-based with the index in position zero being considered even. The input string will consist of only alphabetical characters and spaces. Spaces should only be present when there are multiple words.

Example:
to_weird_case('String'); # => returns 'StRiNg'
to_weird_case('Weird string case') # => returns 'WeIrD StRiNg CaSe'

Happy coding~!

This challenge comes from user xDranik. Thank you to CodeWars, who has licensed redistribution of this challenge under the 2-Clause BSD License!

Want to propose a challenge for a future post? Email yo+challenge@dev.to with your suggestions!

Top comments (32)

La blatte • Aug 6 '19

Here goes a simple oneliner:

toWeirdCase=(s)=>[...s].map((e,i)=>i%2?e.toLowerCase():e.toUpperCase()).join('');

And the result:

toWeirdCase('String'); // "StRiNg"
toWeirdCase('Weird string case'); // "WeIrD StRiNg cAsE"

Sung M. Kim • Aug 6 '19

I believe case should be printed as CaSe as first letter (index 0) should be always capitalized.

La blatte • Aug 7 '19

Indeed! Didn't catch that! Here is a little fix for that:

toWeirdCase=(a)=>a.split` `.map(s=>[...s].map((e,i)=>i%2?e.toLowerCase():e.toUpperCase()).join``).join` `;

which output is:

toWeirdCase('String'); // "StRiNg"
toWeirdCase('Weird string case'); // "WeIrD StRiNg CaSe"

Ken Bellows • Aug 6 '19

Index 0 refers to the first letter of the entire string; we don't need to consider each word separately, just the string as a whole

Sung M. Kim • Aug 6 '19

Sorry about that.
I meant it as index 0 of each word.

the example shows the result should be

to_weird_case('Weird string case') # => returns 'WeIrD StRiNg CaSe'

Ken Bellows • Aug 6 '19 • Edited

Ah, you're right, that's interesting. I hadn't noticed that discrepancy with the capital 'C' in 'CaSe'; that makes this a more interesting challenge!

The original post should probably call that out a little more clearly, because it raises additional questions: Should punctuation count as a word separator? e.g., should 'word-other' become 'WoRd-oThEr' or 'WoRd-OtHeR'? Or should we only worry about letters and spaces? What characters are we considering?

@thepracticaldev , any help here?

Sung M. Kim • Aug 6 '19

For some reason, CodeWars isn't loading for me so won't be able to check the edge cases... 🤔

Ken Bellows • Aug 6 '19 • Edited

Python solution:

toWeirdCase = lambda s: ''.join([c.lower() if i%2 else c.upper() for i,c in enumerate(s)])

print(toWeirdCase('String')) #=> StRiNg
print(toWeirdCase('Weird string case')) #=> WeIrD StRiNg cAsE

EDIT
@dance2die pointed out in this comment that the multi-word example in the post seems to suggest that each word should be considered and cased separately, rather than the whole string. In that case, this becomes a bit more interesting.

Here's a simple modification to account only for spaces separating words:

toWeirdCase = lambda s: ' '.join([wordToWeirdCase(w) for w in s.split(' ')])
wordToWeirdCase = lambda s: ''.join([c.lower() if i%2 else c.upper() for i,c in enumerate(s)])

print(toWeirdCase('String')) #=> StRiNg
print(toWeirdCase('Weird string case')) #=> WeIrD StRiNg CaSe

But this could get a lot more complex if we need to account for things like punctuation and other whitespace characters.

As one last example, here's one that handles alternative whitespace characters using regular expressions:

import re

toWeirdCase = lambda s: (
  s[:re.search(r'\S', s).start() if re.match(r'\s', s) else 0] +   # handle leading whitespace
  ''.join(
    [wordToWeirdCase(w) for w in re.findall(r'\S+(?:\s+)?', s)]
  )
)

wordToWeirdCase = lambda s: ''.join([c.lower() if i%2 else c.upper() for i,c in enumerate(s)])

print(toWeirdCase('String')) #=> 'StRiNg'
print(toWeirdCase('Weird string case')) #=> 'WeIrD StRiNg CaSe'
print(toWeirdCase('  hELLO world\tHOW\'S EVeryTHInG???')) #=> '  HeLlO WoRlD   HoW'S EvErYtHiNg???'

Saurabh Ranjan • Aug 6 '19

In Js ( Many Optimised solutions are already given, just tried different way)

const to_weird_case = (string) => {
    let  newString = [];
    for( let i in string ) {
        if(i%2 == 0){
            newString.push(string[i].toUpperCase());
        } else {
            newString.push(string[i].toLowerCase());
        }
    }
    return newString.join('');
};

to_weird_case('Weird string case');

Andy Zhao (he/him) • Aug 6 '19

Ruby, not optimal 🙃

def to_weird_case(string)
  if string.include? " "
    string.split(" ").map { |word| word.split("") }.each do |letter_array|
      letter_array.each_with_index do|letter, index|
        letter.upcase! if index % 2 == 0 }}.map(&:join).join(" ")
      end
    end
  else
    string.split("").each_with_index do |letter, index|
      letter.upcase! if index % 2 == 0
    end.join
  end
end

Alvaro Montoro • Aug 8 '19 • Edited

JavaScript

function formatText(message) {
    return message.split(" ")
                  .map(function(el) {
                    return el.split('')
                             .map(function(letter, idx) {
                               return idx % 2 === 0 ? letter.toLowerCase() : letter.toUpperCase();
                             })
                             .join('');
                  })
                  .join(' ')
  }

And as an extension, I used that function to create a Sponge Bob Mocking meme generator! (which is the first thing that I thought when I saw the challenge)

LaurentiuMolnar • Aug 7 '19

A simple solution in Javascript:

function toWeirdCase(string) {
  return string.split(' ')
    .map(word => {
      return word.split('')
        .map((char, index) => {
          if (index % 2 === 0) return char.toUpperCase()
          return char
        })
        .join('')
    })
    .join(' ')
}

console.log(toWeirdCase('string'))
console.log(toWeirdCase('Weird string  case'))

ItsASine (Kayla) • Aug 6 '19

At work, we just call this serial killer case :P

Dev Prakash • Sep 10 '19 • Edited

def weird_string (string) :
    result = ""
    for index in range(len(string)) :
        if index % 2 == 0 :
            result += string[index].upper()
        else :
            result += string[index].lower()
    return result

print (weird_string("Weird string case"))

Python one liner


def weird_string (string) :
    result = ("").join([string[i].lower() if i%2 else string[i].upper() for i in range(len(string))])
    return result

print(weird_string("Weird string case"))

K.V.Harish • Oct 5 '19 • Edited

My solution in js

const toWeirdCase = (str = '') => (str.split(' ').map((s) => ([...s].map((char, index) => (index % 2) ? char.toLowerCase() : char.toUpperCase())).join(''))).join(' ');

Sung M. Kim • Aug 6 '19

I've implemented based off of La blatte's answer.

const caser = {
  0: c => c.toUpperCase(),
  1: c => c.toLowerCase()   
}
const mod = i => i % 2
const weirdCase = text => text.split(' ').map(word => 
    [...word].map((c, i) => caser[mod(i)](c)).join('')
).join(' ')

console.log(["String", "Weird string case"].map(weirdCase))

prints,

["StRiNg", "WeIrD StRiNg CaSe"]

View full discussion (32 comments)

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Daily Challenge #34 - WeIrD StRiNg CaSe

Top comments (32)

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