Count letters in a String - A Java Code Example

This example shows how to count letters in a String. We use the Character wrapper class though it could as easily be done with regular expressions.
We simply call the static method isLetter() for each character in the String. This method returns true if it's a letter and false if otherwise. In the example below we use both letters and numbers in the input parameter and the isLetter method will of course return false for the numbers.

The output from the code below will be:

'The input parameter contained 5 letters.'

/**
*
* @author javadb.com
*/
public class Main {

    /**
     * This method counts the number of letters in a String
     */
    public void countLetters(String str) {

        if (str == null)
            return;

        int counter = 0;

        for (int i = 0; i < str.length(); i++) {

            if (Character.isLetter(str.charAt(i)))
                counter++;
        }

        System.out.println("The input parameter contained " + counter + " letters.");
    }


    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().countLetters("abcde123");
    }
}

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