dev.to staff

Posted on Aug 21, 2019

Daily Challenge #46 - ???

#challenge

Today's challenge requires you to write a function which removes all question marks from a given string.

For example: hello? would be hello

This challenge comes from aikedaa here on DEV.

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

Discussion (50)

Vitali Pomanitski • Aug 21 '19 • Edited on Aug 21

I'll do:

echo $string | sed 's/?//g'

TrustmeI'manEngineer

Amin • Aug 21 '19 • Edited on Aug 21

Hey there! Nice to see some bash users here.

You can even use bash without sed using this little trick:

#!/usr/bin/env bash

string="??hello??"

echo $string # "??hello??"
echo ${string//\?/} # "hello"

Try it online.

See Manipulating String.

Vitali Pomanitski • Aug 21 '19

Are you aware of the fish shell? I guess that you're pro+ in the bash, so I can't know about that. If not, check it out. You'll like that! It's a fully auto comopletion shell that is perfect for the home users. For scripts you'll still have to use bash though (ot tcsh, zsh whatsoever....) :)
If not you, hope so somebody will find it useful.

Amin • Aug 21 '19

I've never had the courage to deep dive into the Fish shell honestly but your comment gave me some strength. I'll fire up a Docker container to test it out. Added to my ToDo list! Thanks.

Vitali Pomanitski • Aug 21 '19

hooray!

Vitali Pomanitski • Aug 21 '19

thanks that's nice!

David Wickes • Aug 21 '19 • Edited on Aug 21

sed is overkill. Try tr:

echo "why not use tr?" | tr -d '?'

Vitali Pomanitski • Aug 21 '19

Yap, he is right :)
I'm not yet a Senior developer.

Seiei Miyagi • Aug 21 '19

ruby <3

def remove_question_marks(s)
  s |> delete ??
end

Michael Kohl • Aug 22 '19 • Edited on Aug 22

Ha, you probably confused some people there, especially with the character literal.

Seiei Miyagi • Aug 23 '19

I love weird Ruby syntax😆

TIPS: ?? is known as character literal notation
docs.ruby-lang.org/en/trunk/syntax...

Michael Kohl • Aug 23 '19

I know, that's why I wrote "especially with the character literal" ;-)

Other literals many people don't know are rational numbers (4/3r) and complex numbers (3+2i).

Seiei Miyagi • Aug 23 '19 • Edited on Aug 23

I see. Also % literal is my favorite string literal :)

s = %
here is string, the delimiter is \\n

puts s

Amin • Aug 21 '19

JavaScript

Here is my take to the challenge:

function removeQuestionMarks(input) {
  if (typeof input !== "string") {
    throw new TypeError("First argument expected to be a string");
  } 

  return input.split("?").join("");
}

console.log(removeQuestionMarks("hello?"));
// "hello"

console.log(removeQuestionMarks("hmm? hello??"));
// "hmm hello"

console.log(removeQuestionMarks("hmm? hello?? can i speak to the manager?"));
// "hmm hello can i speak to the manager"

console.log(removeQuestionMarks("?? is anybody there???"));
// " is anybody there"

Source-Code

Available online.

Side-note

By the name of the title in my notifications, I really though that the challenge would be to write a challenge and submit the best to the Dev.to team as they were running out of ideas. Haha!

Peter Kim Frank • Aug 22 '19

By the name of the title in my notifications, I really though that the challenge would be to write a challenge and submit the best to the Dev.to team as they were running out of ideas. Haha!

Please submit challenge ideas! Simply email yo+challenge@dev.to with any proposals and we'll give you credit when we post it :)

George • Aug 21 '19

Tomorrows challenge:

Write a random challenge generator!

Amin • Aug 21 '19

Oh, sounds sexy. I love it! Haha.

Șerbu Vlad Gabriel • Aug 21 '19

x86_64 assembly (System V ABI, GNU assembler), as usual:

bsure.S:

    .global bsure

    .text
bsure:
    xor %eax, %eax
loop:
    mov (%rsi), %cl

    cmp $63, %cl # '?'
    je skip

    mov %cl, (%rdi)
    inc %rdi
    inc %rax
skip:
    inc %rsi

    cmp $0, %cl
    jne loop

    ret

bsure.h:

/* 
 * bsure - remove question marks from a string
 * if dst and src overlap (or match), that's fine
 * returns the number of bytes copied (including the null byte).
 */
size_t bsure(char *dst, char *src);

George • Aug 21 '19 • Edited on Aug 21

Javascript:

const removeQuestionMark = string => string.replace(/\?/g, '')

Called as:

removeQuestionMark('Will this work???') // yes

Important to note, this will also remove the first escape characters (\) and output newlines in template literals as \n

Jay • Aug 21 '19

Rust

fn no_questions (s: &str) -> String {
    s.chars().filter(|&c| c != '?').collect()
}

Playground

Josh • Aug 21 '19 • Edited on Aug 21

... 😐

I mean... that's not even a function to write. It's a function to call.

Elixir:

"What is this? What's happening??" |> String.replace("?", "")

Ruby:

"What is this? What's happening??".gsub("?", "")

JavaScript:

"What is this? What's happening??".replace(/\?/g, "")

Bash:

echo "What is this? What's happening??" | sed s/\?//g

Josh • Aug 22 '19

Okay, I'll bite and imagine that Carmen Sandiego has stolen all the regular expressions!

defmodule DarnYouCarmen do
  # Quick, destroy the question marks before she steals them, too!
  def whats_a_question(string, processed \\ [])
  def whats_a_question("", processed), do: IO.chardata_to_binary(processed)
  def whats_a_question("?"<>string, processed), do: whats_a_question(string, processed)
  def whats_a_question(<<next :: utf8>> <> string, processed), do: whats_a_question(string, [processed, next]
end

DarnYouCarmen.whats_a_question("What is this? What's happening??")
# "What is this What's happening"

Idan Arye • Aug 22 '19

// CharacterRemover.java

package org.stringops.questionmarkremover;

public interface CharacterRemover {
    /**
     * TODO
     * @param String source TODO
     * @return String TODO
     */
    public String removeCharacter(String source);
}

// CharacterRemoverFactory.java

package org.stringops.questionmarkremover;

public interface CharacterRemoverFactory {
    /**
     * TODO
     * @return CharacterRemover TODO
     */
    public CharacterRemover createCharacterRemover();
}

// QuestionMarkRemover.java

package org.stringops.questionmarkremover;

import java.io.StringReader;
import java.io.InputStreamReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

public class QuestionMarkRemover implements CharacterRemover {
    /**
     * TODO
     * @param String source TODO
     * @return String TODO
     */
    public String removeCharacter(String source) {
        StringReader reader = new StringReader(source);
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        try {
            int dataFromReader = reader.read();
            while (dataFromReader != -1) {
                if (dataFromReader != '?') {
                    outputStream.write(dataFromReader);
                }
                dataFromReader = reader.read();
            }
        } catch (IOException e) {
            // TODO: handle the exception
        }
        byte[] byteArray = outputStream.toByteArray();
        return new String(byteArray);
    }
}

// QuestionMarkRemoverFactory.java

package org.stringops.questionmarkremover;

public class QuestionMarkRemoverFactory implements CharacterRemoverFactory {
    /**
     * TODO
     * @return CharacterRemover TODO
     */
    public CharacterRemover createCharacterRemover() {
        return new QuestionMarkRemover();
    }
}

And to use it:

import org.stringops.questionmarkremover.*;

public class App {
    /**
     * TODO
     * @param String[] args TODO
     * @return void TODO
     */
    public static void main(String[] args) {
        CharacterRemoverFactory characterRemoverFactory = new QuestionMarkRemoverFactory();
        CharacterRemover characterRemover = characterRemoverFactory.createCharacterRemover();

        System.out.println(characterRemover.removeCharacter("hello?"));
    }
}

Oleksii Filonenko • Aug 22 '19

private static final OpinionAboutJava opinionAboutJava = OpinionAboutJavaFactory.getOpinionAboutJava("ugh...");

Idan Arye • Aug 22 '19

NOOOO!!!

You need to create an instance of the OpinionAboutJavaFactory! You can just have a static getOpinionAboutJava method! Now your code is not SOLID!

David Wickes • Aug 22 '19

ENTERPRISE

Ben Halpern • Aug 21 '19

Ruby

def no_more_questions(string)
  string.gsub("?", "")
end

Matt Ellen • Aug 21 '19 • Edited on Aug 21

(javascript)

function noMoreQM(input)
{
  return input.replace(/\?/g, '');
}

Uses a simple regular expressions with the global (g) modifier to find all the ? (this needs to be escaped in a regular expression, so \?) and replace them with the empty string ''.

Roadirsh • Aug 21 '19 • Edited on Aug 21

PHP :

str_replace('?', '', $string)

Amin • Aug 21 '19

Hey there! Awesome to see some PHP users. PHP IS NOT DEAD! Haha.

But you are halfway done buddy!

Today's challenge requires you to write a function which removes all question marks from a given string.

Roadirsh • Aug 21 '19

okay okay let's do a wrapper function then :D

function myOwnStrReplaceBecauseIDontLikeSnakeCase($string) {
  return str_replace('?', '', $string);
}

Amin • Aug 21 '19

That function name tho. haha!

E. Choroba • Aug 22 '19

Perl solution:

my $str = 'a?b?c?';
say $str =~ tr/?//dr;

The tr operator works like the tr shell util. /d means non-replaced characters are deleted, /r returns the value instead of modifying the bound variable.

Chris Achard • Aug 21 '19

Even though this is a simple one - it's really interesting to see all of the different ways you can do it!

But I agree with Josh - it's built into most languages :)

str.replace("?", "")

Vitali Pomanitski • Aug 21 '19

Bash somebody?

JavaScript Room • Aug 21 '19

This one works for me. Since Bash doesn't support the global flag for regular expressions I had to iterate over the input string...

removeQuestionMark () {
    result=""
    while read -n 1 char ; do
        if [ "$char" != "?" ] ; then
            result="$result$char"
        fi
    done <<< $1
    echo $result
}

removeQuestionMark "h?e?l?l?o?" # prints "hello"

David Wickes • Aug 21 '19

Try tr instead. 😁

Vitali Pomanitski • Aug 21 '19

"the global flag in regular expression"
You've got regex for search in bash and regex for replace.
For replace, you've got sed. Are you familiar with sed? People usually skip it when learning bash for themselves on their own.

JavaScript Room • Aug 22 '19

I intentionally avoided using sed this time, wanted to implement it with "pure" Bash. Using sed the implementation, of course, becomes much shorter.

Craig McIlwrath • Aug 21 '19

Haskell:

removeQuestionMarks :: String -> String
removeQuestionMarks = filter (/='?')

Amin • Aug 22 '19 • Edited on Aug 22

Similar in Elm (but we have to use wrapping parenthesis for binary operators).

removeQuestionMarks : String -> String
removeQuestionMarks = String.filter ((/=) '?')

SavagePixie • Aug 21 '19

const questionToStatememt = str => str.replace(/\?+/g, '')

K.V.Harish • Oct 5 '19

My solution in js

const removeQuestionMark = (str) => str.replace(/\?/gi, '');

Ganesh Raja • Aug 22 '19

Python:

print(s.replace('?',''))

Jarod Smith • Aug 21 '19

const removeQuestionMarks = str => str.replace(/\?+/g,'');

Stephanie Handsteiner • Aug 21 '19

PHP:

$string = "Some string with question marks??!!";
echo $string = str_replace("?", "", $string);

willsmart • Aug 21 '19 • Edited on Aug 21

Well, since we're doing cmd things...

read s; echo "${s//\?/}"

(bash on mac)

Vivek97 • Aug 22 '19 • Edited on Aug 22

System.out.println("??he?llo".replace("?", " "));

Mat-R-Such • Aug 6 '20

Python

def remove_(text):  return text.replace('?','')

print(remove_('He?l?lo?'))

Héctor Pascual • Aug 26 '19

As simple as it sounds, in python :

lambda s : re.sub(r'\?','', s)

View full discussion (50 comments)

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Daily Challenge #46 - ???

Discussion (50)

TrustmeI'manEngineer

Rust

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