How to get the number of occurrences of each letter in specified string in JavaScript ?
Last Updated :
31 Mar, 2023
In this article, we are given a string, our task is to find the occurrence of a character in the string with the help of a 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 the map with a key for each character of the string, and the value for each is 0.
- We iterate over the string and increment the value of the character.
- Finally, print key-values of the map.
Example: This example shows the use of the above-explained approach.
Javascript
<script>
function printans( ans )
{
for ( let [ key ,value] of ans)
{
console.log(`${key} occurs ${value} times` );
}
}
function count( str , outp_map )
{
for ( let i = 0 ;i < str.length ;i++)
{
let k = outp_map.get(str[i]);
outp_map.set(str[i], k+1) ;
}
printans(outp_map);
}
function count_occurs( test , callback )
{
if ( test.length === 0 )
{
console.log( " empty string " );
return ;
}
else
{
let ans = new Map();
for ( let i = 0 ;i < test.length;i++)
{
ans.set(test[i], 0);
}
callback( test ,ans);
}
}
let test = "helloworld" ;
count_occurs( test ,count);
</script>
|
Output:
h occurs 1 times
e occurs 1 times
l occurs 3 times
o occurs 2 times
w occurs 1 times
r occurs 1 times
d occurs 1 times
Approach 2: In this approach, we use nested for loop to iterate over the string and count for each character in the string.
- First, initialize count with value 0 for the ith value of the string.
- Now we iterate over the string if ith value matches with the character, increasing the count value by 1.
- Finally, print the value of the count.
Example: This example shows the use of the above-explained approach.
Javascript
<script>
function count_occur( str )
{
if ( str.length == 0 )
{
console.log( "Invalid string" )
return ;
}
for ( let i = 0 ;i < str.length ;i++)
{
let count = 0;
for ( let j = 0 ;j < str.length ;j++)
{
if ( str[i] == str[j] && i > j )
{
break ;
}
if ( str[i] == str[j] )
{
count++;
}
}
if ( count > 0)
console.log(`${str[i]} occurs ${count} times`);
}
}
let 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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