How do I check each individual digit within a string?

Question

I was given the challenge of converting a string of digits into 'fake binary' on Codewars.com, and I am to convert each individual digit into a 0 or a 1, if the number is less than 5 it should become a 0, and if it's 5 or over it should become a 1. I know how to analyze the whole string's value like so:

function fakeBin(x){
if (x < 5)
return 0;
else return 1;
}

This however, analyzes the value of the whole string, how would I go about analyzing each individual digit within the string rather than the whole thing?

Note: I have already looked at the solutions on the website and don't understand them, I'm not cheating.

Firstly, you'll need to make sure you are getting string. If not, then you will need to typecast it to string and then split it using `x.split("");` And then loop through it to generate your output string. — Yogesh Mistry, Mar 04 '17 at 05:28
How are the digits delimited? Are numbers in string all `<=9`? — guest271314, Mar 04 '17 at 05:47
Do you want to change the digits in place or do you want to return a new string? — Jordan Bonitatis, Mar 04 '17 at 05:55
@JordanBonitatis - Given that JS strings are immutable, it will have to be a new string. — nnnnnn, Mar 04 '17 at 06:07

score 3 · Answer 1 · answered Mar 04 '17 at 05:59

You can do it in one line with two simple global string replacement operations:

function fakeBin(x){
  return ("" + x).replace(/[0-4]/g,'0').replace(/[5-9]/g,'1');
}

console.log(fakeBin(1259))
console.log(fakeBin(7815))
console.log(fakeBin("1234567890"))

The ("" + x) part is just to ensure you have a string to work with, so the function can take numbers or strings as input (as in my example calls above).

score 1 · Answer 2 · answered Mar 04 '17 at 05:50

1

Simple javascript solution to achieve expected solution

function fakeBin(x){
 x = x+'' ;
var z =[];
for(var i=0;i< x.length;i++){
  if((x[i]*1)<5){
     z[i] =0;
   }else{
    z[i]=1;
  }
}
  return z
}

console.log(fakeBin(357))

answered Mar 04 '17 at 05:50

divya reddy

139
1
11

super ugly code, +1. I truly didn't know it could be done this ugly. – Mar 04 '17 at 06:30

Jonathan Portorreal · Answer 3 · 2017-03-04T05:38:22.060

Split the string and apply the current function you have to each element of the string. You can accomplish this with map or with reduce:

function fakeBin(x) {
  
  x = x.split('');
  
  let toBin = x => {
    if (x < 5)
      return 0;
    else return 1
  }
  
  return x.map(toBin).join('');
}

console.log(fakeBin("2351"));

refactored

function fakeBin(x) {
  x = [...x];

  let toBin = x => x < 5 ? 0 : 1;

  return x.map(toBin).join('');
}

console.log(fakeBin("2351"));

reduce

function fakeBin(x) {

  let toBin = x => x < 5 ? 0 : 1;

  return [...x].reduce((acc,val) => acc + toBin(val), "");

}

console.log(fakeBin("23519"));

score 0 · Answer 4 · answered Mar 04 '17 at 05:30

0

if you are in java you can use

charAt()

and you make a for with the word length and you can check one by one

for(int i = 0; i < text.length(); i++){
yourfunction(texto.charAt(i));
}

answered Mar 04 '17 at 05:30

Sergio Camilo

11
1

Jordan Bonitatis · Accepted Answer · 2017-03-04T06:05:50.157

The snippet below will take a string and return a new string comprised of zeros and/or ones based on what you described.

We use a for ...of loop to traverse the input string and will add a 0 or 1 to our return array based on whether the parsed int if greater or less than 5.

Also note that we are checking and throwing an error if the character is not a number.

const word = "1639";

const stringToBinary = function(str) {
  let ret = [];
  for (const char of word) {
     if (Number.isNaN(parseInt(char, 10))) {
       throw new Error(`${char} is not a digit!`);
     } else {
       const intVal = parseInt(char, 10);
       ret.push(intVal > 5 ? 1 : 0);
     }
  }
  return ret.join('');
};

console.log(stringToBinary(word));

score 0 · Answer 6 · answered Mar 04 '17 at 06:00

0

You can use String.prototype.replace() with RegExp /([0-4])|([5-9])/g to match 0-4, 5-9, replace with 0, 1 respectively

let str = "8539734222673566";

let res = str.replace(/([0-4])|([5-9])/g, (_, p1, p2) =>  p1 ? 0 : 1);
 
console.log(res);

answered Mar 04 '17 at 06:00

guest271314

1
15
104
177

How do I check each individual digit within a string?

6 Answers6

refactored

reduce

Linked