Frequency count of string occured using collections

Question

Frequency count of string occured.

Can u say any alternative code for following.

https://code.sololearn.com/cmo5wCA8Tgfe/?ref=app

How to write it through collections!

Answer 1

I'd suggest you use a HashTable.

// Creation
Hashtable<String, Integer> counts = new Hashtable<String, Integer>();

// Inserting the first element if it doesn't exist, updating otherwise.
// Please replace "<user input>" to make this work.
if (!counts.containsKey(<user input>))
counts.put(<user input>, 0);
else
counts.put(<user input>, counts.get(<user input>) + 1);

// Results time!
Enumeration keys = counts.keys();
while (keys.hasMoreElements()) {
String key = keys.nextElement();
Integer value = counts.get(key);
System.out.println(key + " -> " + value.toString());
}

Reference: https://www.geeksforgeeks.org/hashtable-in-java/

Answer 2

Felipe BF
can u send me whole code plz.
i tried to get but it is not working
https://code.sololearn.com/cDP95drxWjE1/?ref=app

Answer 3

Haritha Vuppula
There were quite a few errors in your program.

Please study them by comparing your version against this one.

I forgot "nextElement" returns an Object.

https://code.sololearn.com/c7rBGP8mCS3G/?ref=app

Answer 4

Felipe BF
can u clear my doubts
https://code.sololearn.com/ca5FQ0tGAbSS/?ref=app

Answer 5

Haritha Vuppula

1. "nextElement" returns an Object. In order to get the String we need, we've got to cast the result to String. I took advantage of the fact "toString" returns a String to make the cast. You can do that when getting the next element, as you pointed out.

2. As a Hashtable accepts Objects as keys and values, I used "Integer" for the values part to avoid an error later in the code if I'd stuck to using the primitive data type "int". An "Integer" is like an "int", but made as a class to use it where an Object is expected.

Reference for how Java treats primitives and their equivalent classes: https://stackoverflow.com/a/22471048