CODEWITHSUNDEEP
javascript
jkalandarov
jkalandarov

Reputation: 685

Filter Repeating Character Strings

I need to create a function (in JS) that takes an array as an argument and returns new array by filtering it (argument) and leaving elements with repetitive characters.

identicalFilter(["aaaaaa", "bc", "d", "eeee", "xyz"]) // => ["aaaaaa", "d", "eeee"]
identicalFilter(["88", "999", "22", "5454", "31333"]) // => ["88", "999", "22"]

So far, I've come up with this code and really screwed up

function identicalFilter(arr) {
    let newArr = [];
    let tempArr = arr.forEach(key => {
        return key.split('');
    });
    for (let i = 0; i < tempArr.length; i++){
        let count = 0;
        for (let k = 0; k < tempArr[i].length; k++){
            if (tempArr[i][0]===tempArr[i][i]) {
                count++;
            }
            if (count === temArr[i].length){
                newArr.push(tempArr[i]);
            }
        }
    }
    return newArr;
}

SOS

Upvotes: 1

Views: 928

Answers (2)

brk
brk

Reputation: 50326

You can use reduce & every. Inside the reduce callback get the first character and then use every to check if all elements are same

function identicalFilter(arr) {
  if (arr.length === 0) {
    return [];
  }
  return arr.reduce((acc, curr) => {
    let firstChar = curr.charAt(0);
    let isSame = curr.split('').every(item => item === firstChar);
    if (isSame) {
      acc.push(curr)
    }
    return acc;
  }, [])
}





console.log(identicalFilter(["aaaaaa", "bc", "d", "eeee", "xyz"]))
console.log(identicalFilter(["88", "999", "22", "5454", "31333"]))

Upvotes: 1

CertainPerformance
CertainPerformance

Reputation: 371019

How about using a regular expression instead? Match and capture the first character, then backreference that character as many times as needed until reaching the end of the string:

const identicalFilter = arr => arr.filter(
  str => /^(.)\1*$/.test(str)
);

console.log(identicalFilter(["aaaaaa", "bc", "d", "eeee", "xyz"])) // => ["aaaaaa", "d", "eeee"]
console.log(identicalFilter(["88", "999", "22", "5454", "31333"])) // => ["88", "999", "22"]

If you don't like regular expressions, you could also turn the string into an array and check that .every one of its characters is the same as the first:

const identicalFilter = arr => arr.filter((str) => {
  const arr = [...str];
  const firstChar = arr.shift();
  return arr.every(char => char === firstChar);
});

console.log(identicalFilter(["aaaaaa", "bc", "d", "eeee", "xyz"])) // => ["aaaaaa", "d", "eeee"]
console.log(identicalFilter(["88", "999", "22", "5454", "31333"])) // => ["88", "999", "22"]

Upvotes: 1

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