In this article, we will learn how to count number of vowels and consonants in a String ignoring space characters
Count Vowels and Consonants :
- Using Java 8 – String.char() and Stream.filter() and Stream.count() methods
- Using String.toCharArray() method
- Using String.charAt(index) method
1. Using Java 8 – String.char() and Stream.filter() and Stream.count() methods
- First, we will check whether input String is not null otherwise throw new IllegalArgumentException to the invoking method
- Remove space characters if any using String.replaceAll(old, new)
- After necessary null check and removing space characters, get Stream using Stream.chars() method
- Vowels – Filter out vowel characters using Stream.filter() method and count them using count() method
- Consonants – Filter out non-vowel characters using Stream.filter() method and count them using count() method
- Finally, we will print vowel & consonants count to the console
CountVowelsAndConsonantsUsingJava8.java
package in.bench.resources.string.operation;
public class CountVowelsAndConsonantsUsingJava8 {
// global variables
private static long VOWELS = 0;
private static long CONSONANTS = 0;
// main() method
public static void main(String[] args) {
// test string
String str = "BenchResourcesNet has very useful examples and tips on Java";
// print to console - original String
System.out.println("Input String :- \n" + str);
// call method
countVowelsAndConsonants(str);
// print to console
System.out.println("\nVowel count is = " + VOWELS);
System.out.println("Consonant count is = " + CONSONANTS);
}
/**
* this method is used to count vowels & consonants using Java 8 Stream
*
* @param str
*/
public static void countVowelsAndConsonants(String str) {
// check whether input string is not null
if(null == str) {
throw new IllegalArgumentException("Input String cannot be null");
}
// replace all spaces - ignore space characters
str = str.replaceAll(" ", "");
// count vowels
VOWELS = str // original source or string
.chars() // get character stream
.filter(ch -> (
'a' == ch || 'e' == ch || 'i' == ch || 'o' == ch || 'u' == ch ||
'A' == ch || 'E' == ch || 'I' == ch || 'O' == ch || 'U' == ch)
) // filter out vowels
.count(); // count vowels
// count consonants
CONSONANTS = str // original source or string
.chars() // get character stream
.filter(ch -> (
ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z')
) // check whether it is in range
.filter(ch -> (
'a' != ch && 'e' != ch && 'i' != ch && 'o' != ch && 'u' != ch &&
'A' != ch && 'E' != ch && 'I' != ch && 'O' != ch && 'U' != ch)
) // filter out non-vowels
.count(); // count consonants
}
}
Output:
Input String :-
BenchResourcesNet has very useful examples and tips on Java
Vowel count is = 19
Consonant count is = 32
2. Using String.toCharArray() method
- First, we will check whether input String is not null otherwise throw new IllegalArgumentException to the invoking method
- Remove space characters if any using String.replaceAll(old, new) and convert to char[] array using String.toCharArray() method
- Iterate through char[] array, reading one character at a time,
- Vowels – Check if the character in question is (a, e, i, o, u) or (A, E, I, O, U) then increment vowel count by 1
- Consonants – Check if the character in question is not (a, e, i, o, u) or (A, E, I, O, U) and falls within the range of (a-z) or (A-Z) then increment consonant count by 1
- Finally, we will print vowel & consonant count to the console
CountVowelsAndConsonantsUsingToCharArray.java
package in.bench.resources.string.operation;
public class CountVowelsAndConsonantsUsingToCharArray {
// global variables
private static int VOWELS = 0;
private static int CONSONANTS = 0;
// main() method
public static void main(String[] args) {
// test string
String str = "BenchResourcesNet has very useful examples and tips on Java";
// print to console - original String
System.out.println("Input String :- \n" + str);
// call method
countVowelsAndConsonants(str);
// print to console
System.out.println("\nVowel count is = " + VOWELS);
System.out.println("Consonant count is = " + CONSONANTS);
}
/**
* this method is used to count vowels & consonants
*
* @param str
*/
public static void countVowelsAndConsonants(String str) {
// check whether input string is not null
if(null == str) {
throw new IllegalArgumentException("Input String cannot be null");
}
// replace all spaces & convert to character arrays - ignore space characters
char[] chArray = str.replaceAll(" ", "").toCharArray();
// iterate String characters and count vowels & consonants
for(int index = 0; index < chArray.length; index++) {
// read one character at a time
char ch = chArray[index];
// check for vowels
if('a' == ch || 'e' == ch || 'i' == ch || 'o' == ch || 'u' == ch
|| 'A' == ch || 'E' == ch || 'I' == ch || 'O' == ch || 'U' == ch) {
// increment count by 1
VOWELS++;
}
else if((ch >= 'a' && ch <= 'z') ||
(ch >= 'A' && ch <= 'Z')) { // check for consonants
// increment count by 1
CONSONANTS++;
}
else {
System.out.println("\n" + ch + " isn't Vowel or Consonant");
}
}
}
}
Output:
Input String :-
BenchResourcesNet has very useful examples and tips on Java
Vowel count is = 19
Consonant count is = 32
3. Using String.charAt(index) method
- First, we will check whether input String is not null otherwise throw new IllegalArgumentException to the invoking method
- Remove space characters if any using String.replaceAll(old, new)
- Iterate using for-loop starting with 0 till length of the input String and get single character from the given String passing index-position using String.charAt(index)
- Vowels – Check if the character in question is (a, e, i, o, u) or (A, E, I, O, U) then increment vowel count by 1
- Consonants – Check if the character in question is not (a, e, i, o, u) or (A, E, I, O, U) and falls within the range of (a-z) or (A-Z) then increment consonant count by 1
- Finally, we will print vowel & consonant count to the console
CountVowelsAndConsonantsInJava.java
package in.bench.resources.string.operation;
public class CountVowelsAndConsonantsInJava {
// global variables
private static int VOWELS = 0;
private static int CONSONANTS = 0;
// main() method
public static void main(String[] args) {
// test string
String str = "BenchResourcesNet has very useful examples and tips on Java";
// print to console - original String
System.out.println("Input String :- \n" + str);
// call method
countVowelsAndConsonants(str);
// print to console
System.out.println("\nVowel count is = " + VOWELS);
System.out.println("Consonant count is = " + CONSONANTS);
}
/**
* this method is used to count vowels & consonants
*
* @param str
*/
public static void countVowelsAndConsonants(String str) {
// check whether input string is not null
if(null == str) {
throw new IllegalArgumentException("Input String cannot be null");
}
// replace all spaces - ignore space characters
str = str.replaceAll(" ", "");
// iterate String characters and count vowels & consonants
for(int index = 0; index < str.length(); index++) {
// read one character at a time
char ch = str.charAt(index);
// check for vowels
if('a' == ch || 'e' == ch || 'i' == ch || 'o' == ch || 'u' == ch
|| 'A' == ch || 'E' == ch || 'I' == ch || 'O' == ch || 'U' == ch) {
// increment vowel count by 1
VOWELS++;
}
else if((ch >= 'a' && ch <= 'z') ||
(ch >= 'A' && ch <= 'Z')) { // check for consonants
// increment consonant count by 1
CONSONANTS++;
}
else {
System.out.println("\n" + ch + " isn't Vowel or Consonant");
}
}
}
}
Output:
Input String :-
BenchResourcesNet has very useful examples and tips on Java
Vowel count is = 19
Consonant count is = 32
References:
- https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#charAt-int-
- https://docs.oracle.com/javase/8/docs/api/java/lang/String.html#toCharArray–
- https://docs.oracle.com/javase/8/docs/api/java/lang/CharSequence.html#chars–
- https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html#filter-java.util.function.Predicate-
- https://docs.oracle.com/javase/8/docs/api/java/util/stream/IntStream.html#count–
Happy Coding !!
Happy Learning !!
