Java Program to Count Strings and Integers from an Array

Java Program to Count Strings and Integers from an Array

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In the previous article, we have seen Java Program to Calculate Standard Deviation

In this article we are going to see how to Count Strings and Integers from an Array using Java programming language.

Java Program to Count Strings and Integers from an Array

Array is a data structure which stores a fixed size sequential collection of values of single type. Where with every array elements/values memory location is associated. Each array elements have it’s own index where array index starts from 0.

In Array set of variables referenced by a single variable name and it’s array index position. It is also called as a container object which contains elements of similar type.

Declaration of an array:

dataType[] arrayName; (or)                              //Declaring an array
dataType []arrayName; (or)
dataType arr[];

Instantiation of an Array:

arrayName = new datatype[size];                    //Allocating memory to array

Combining both Statements in One:

dataType[] arrayName = new dataType[size] //Declaring and Instantiating array

Initialization of an Array:

arrayName[index-0]= arrayElement1             //Initializing the array

...

arrayName[index-s]= arrayElementS

Combining all Statements in One:

dataType arrayName[ ]={e1,e2,e3};               //declaration, instantiation and initialization

Let’s see different ways to count strings and integers from an array.

Method-1: Java Program to Count Strings and Integers from an Array By Static Initialization of Array Elements

Approach Using try-catch:

  • Method Integer.parseInt() throws “NumberFormatException” – if the string does not contain a parsable integer, we can take advantage of this to solve this problem.
  • Initialize two variables stringCount = 0 and intCount = 0.
  • Iterate over the array.
  • In try block use Integer.parseInt() to check if the ith element is an integer or not.
  • If no then it’ll move to catch block and we can increment the stringCount variable.
  • If yes, it will continue to run inside the try block and we can increment intCount variable.

Program:

import java.util.Arrays;

public class Main 
{
    public static void main(String arg[]) 
    {
        // enter string u want here.
        String x[] = { "Raj", "77", "101", "99", "Jio" };
        countIntnString(x);
    }

    private static void countIntnString(String[] arr) {
        int intCount = 0, stringCount = 0;

        // scan the string.
        for (String i : arr) {
            // check if string is integer or not using try catch
            try 
            {
                Integer.parseInt(i);
                intCount++;
            } 
            catch (NumberFormatException e) 
            {
                stringCount++;
            }
        }
        // show the numeric and string value after counting.
        System.out.println("Array \"" + Arrays.toString(arr) + "\" contains " + intCount + " integers and " + stringCount + " strings.");
    }
}



Output:

Array "[Raj, 77, 101, 99, Jio]" contains 3 integers and 2 strings.

Method-2: Java Program to Count Strings and Integers from an Array By Dynamic Initialization of Array Elements

Approach:

  • Create scanner class object.
  • Ask use length of the array.
  • Initialize the array with given size.
  • Ask the user for array elements.
  • Iterate over the array.
  • Check if the element is numerical using regex.
  • If yes, increment intCount by one.
  • If no, increment stringCount by one.

Program:

import java.util.Arrays;
import java.util.Scanner;

public class Main
{
    public static void main(String arg[]) 
    {
        // enter string u want here.
        // create scanner class object
        Scanner sc = new Scanner(System.in);
        // take input from user for array size
        System.out.print("Enter the size of array: ");
        int n = sc.nextInt();
        // extra Scanner.nextLine() to consume the newline character due to
        // enter key else it will skip the next nextLine() inside the loop.
        sc.nextLine();
        // initialize array with size n
        String[] arr = new String[n];
        // take input from user for array elements 
        System.out.println("Enter array elements: ");
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextLine();
        }
        countIntnString(arr);
    }

    private static void countIntnString(String[] arr) 
    {
        int intCount = 0, stringCount = 0;
        // check if the element is numerical
        for (String i: arr) 
        {
            if (i.matches("[0-9]+")) 
            {
                intCount++;
            } 
            else 
            {
                stringCount++;
            }
        }
        // show the numeric and string value after counting.
        System.out.println("Array \"" + Arrays.toString(arr) + "\" contains " + intCount + " integers and " + stringCount + " strings.");
    }
}



Output:

Enter the size of array: 5
Enter array elements: 
raj
66
abc
90
jar
Array "[raj, 66, abc, 90, jar]" contains 2 integers and 3 strings.

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