How to get the number of occurrences of each letter in specified string in JavaScript ?
Given a string, our task is finding the occurrence of a character in the string with the help of user-defined function.
Example:
Input : "hello"
Output : h occur 1 times
e occur 1 times
l occur 2 times
o occur 1 times
Explanation : here "hello" have 1 h, so it have 1 value.
as same e have 1, l have 2 , o have 1.
Example 2:
Input : "did"
Output: d occur 2 times
i occur 1 times
Approach 1: In this approach we use a map data structure to store the number of times characters occur.
- First we initialize map with key each character of string and value for each is 0.
- We iterate over string and increment value of the character.
- Finally, print key-values of the map.
Example:
Javascript
<script>//function to print occurrence of characterfunction printans( ans ){ for( let [ key ,value] of ans) { // if() console.log(`${key} occurs ${value} times` ); }}// function count occurrence of characterfunction count( str , outp_map ){ for( let i = 0 ;i < str.length ;i++) { let k = outp_map.get(str[i]); outp_map.set(str[i], k+1) ; } //calling print function printans(outp_map);}//function create map to count characterfunction count_occurs( test , callback ){ //checking string is valid or not if( test.length === 0 ) { console.log(" empty string "); return ; } else { // map for storing count values let ans = new Map(); for( let i = 0 ;i < test.length;i++) { ans.set(test[i], 0); } callback( test ,ans); }}// test string let test = "helloworld";count_occurs( test ,count);</script> |
Output:
h occurs 1 times e occurs 1 times l occurs 3 times o occurs 2 times w occurs 1 times r occurs 1 times d occurs 1 times
Approach 2: In this approach, we use nested for loop to iterate over string and count for each character in the string.
- First initialize count with value 0 for ith value of string.
- Now we iterate over string if ith value matches with the character, increase the count value by 1.
- Finally, print the value of count.
Example:
Javascript
<script>// function that count character occurrences in string function count_occur( str ){ // checking string is valid or not if( str.length == 0 ) { console.log("Invalid string") return; } //cor loop to iterate over string for( let i = 0 ;i < str.length ;i++) { //variable counting occurrence let count = 0; for( let j = 0 ;j < str.length ;j++) { if( str[i] == str[j] && i > j ) { break; } if( str[i] == str[j] ) { count++; } } if( count > 0) console.log(`${str[i]} occurs ${count} times`); }}// test stringlet test_str = "gfghello";count_occur( test_str);</script> |
Output:
g occurs 2 times f occurs 1 times h occurs 1 times e occurs 1 times l occurs 2 times o occurs 1 times
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