how can i count chars from word which in the array?-CodePudding

i have an array ["academy"] and i need count chars from the string in the array.

output:

a:2
c:1
d:1
e:1
m:1
y:1

like this

i tried two for loops

function sumChar(arr){
    let alph="abcdefghijklmnopqrstuvxyz";
    let count=0;
    for (const iterator of arr) {
        for(let i=0; i<alph.length; i  ){
            if(iterator.charAt(i)==alph[i]){
                count  ;
                console.log(`${iterator[i]} : ${count}`);
                count=0;
            }
        }
    }
}
console.log(sumChar(["abdulloh"]));

it works wrong

Output:

a : 1
b : 1
h : 1
undefined

CodePudding user response：

To count the number of occurrences of each character in a string, you can use a for loop to iterate through the string and add each character to an object as a key, with the value being the number of times it occurs. Here is an example:

// create an empty object to store the character counts
var charCounts = {};

// get the string from the array
var str = ["academy"][0];

// iterate through the string and count the occurrences of each character
for (var i = 0; i < str.length; i  ) {
  var char = str[i];
  if (charCounts[char] === undefined) {
    // if the character has not been encountered before, set its count to 1
    charCounts[char] = 1;
  } else {
    // if the character has been encountered before, increment its count by 1
    charCounts[char]  ;
  }
}

// print the character counts
for (var char in charCounts) {
  console.log(char   ": "   charCounts[char]);
}

CodePudding user response：

Here's a concise method. [...new Set(word.split(''))] creates an array of letters omitting any duplicates. .map takes each letter from that array and runs it through the length checker. ({ [m]: word.split(m).length - 1 }) sets the letter as the object key and the word.split(m).length - 1is a quick way to determine how many times that letter shows up.

const countLetters = word => (
  [...new Set(word.split(''))].map(m => ({
    [m]: word.split(m).length - 1
  })))

console.log(countLetters("academy"))

CodePudding user response：

You can check the occurrences using regex also. in this i made a method which checks for the character in the string. Hope it helps.

word: string = 'abcdefghijklkmnopqrstuvwxyzgg';
charsArrayWithCount = {};
CheckWordCount(): void {
    for(var i = 0;i < this.word.length; i  ){
        if(this.charsArrayWithCount[this.word[i]] === undefined){
            this.charsArrayWithCount[this.word[i]] = this.charCount(this.word, this.word[i]);
        }
    }
    console.log(this.charsArrayWithCount);
}
charCount(string, char) {
    let expression = new RegExp(char, "g");
    return string.match(expression).length;
}