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Método isLetter() do caractere Java

O método isLetter(char ch) da classe Character determina se o caractere fornecido (ou especificado) é uma letra ou não.

Um caractere é considerado uma letra se o tipo de categoria geral fornecido pelo Character.getType(ch) for um dos seguintes:

  • LETRA MAIÚSCULA.
  • LETRA MINÚSCULA.
  • TITLECASE_LETTER.
  • MODIFICADOR_LETTER.
  • OTHER_LETTER

Sintaxe

 public static boolean isLetter(char ch)

Parâmetro

CH : É o personagem que precisa ser testado.

Valor de retorno

O método isLetter(char ch) retorna um valor booleano, ou seja, verdadeiro se o caractere fornecido (ou especificado) for uma letra. Caso contrário, o método retornará falso.

Exemplo 1

 public class JavaCharacterisLetterExample1 { public static void main(String[] args) { // Create three char primitives ch1, ch2 and ch3. char ch1, ch2, ch3; // Assign the values to ch1, ch2 and ch3. ch1 = 'A'; ch2 = '9'; ch3 = 'e'; // Create three boolean primitives b1, b2 and b3; boolean b1, b2, b3; // Check whether ch1, ch2 and ch3 are letters or not and assign the results to b1, b2 and b3. b1 = Character.isLetter(ch1); b2 = Character.isLetter(ch2); b3 = Character.isLetter(ch3); String str1 = 'The character '+ch1 + ' is a letter: ' + b1; String str2 = 'The character '+ch2 + ' is a letter: ' + b2; String str3 = 'The character '+ch3 + ' is a letter: ' + b3; // Print the values of b1, b2 and b3. System.out.println( str1 ); System.out.println( str2 ); System.out.println( str3 ); } }
Teste agora

Saída: 

 The character A is a letter: true The character 9 is a letter: false The character e is a letter: true

Exemplo 2

 public class JavaCharacterisLetterExample2 { public static void main(String[] args) { // Create three char primitives ch1, ch2 and ch3. char ch1, ch2, ch3; // Assign the values to ch1, ch2 and ch3. ch1 = '1'; ch2 = '*'; ch3 = 'e'; // Create three boolean primitives b1, b2 and b3; boolean b1, b2, b3; // Check whether if ch1, ch2 and ch3 are letters or not and assign the result to b1, b2 and b3. b1 = Character.isLetter(ch1); b2 = Character.isLetter(ch2); b3 = Character.isLetter(ch3); String str1 = 'The character '+ch1 + ' is a letter: ' + b1; String str2 = 'The character '+ch2 + ' is a letter: ' + b2; String str3 = 'The character '+ch3 + ' is a letter: ' + b3; // Print the values of b1, b2 and b3. System.out.println( str1 ); System.out.println( str2 ); System.out.println( str3 ); } }
Teste agora

Saída: 

 The character 1 is a letter: false The character * is a letter: false The character e is a letter: true

Exemplo 3

 public class JavaCharacterisLetterExample3 { public static void main(String[] args) { // Create three char primitives ch1, ch2 and ch3. char ch1, ch2, ch3; // Assign the values to ch1, ch2 and ch3. ch1 = '1'; ch2 = ')'; ch3 = '*'; // Create three boolean primitives b1, b2 and b3; boolean b1, b2, b3; // Check whether ch1, ch2 and ch3 are letters or not and assign the result to b1, b2 and b3. b1 = Character.isLetter(ch1); b2 = Character.isLetter(ch2); b3 = Character.isLetter(ch3); String str1 = 'The character '+ch1 + ' is a letter: ' + b1; String str2 = 'The character '+ch2 + ' is a letter: ' + b2; String str3 = 'The character '+ch3 + ' is a letter: ' + b3; // Print the values of b1, b2 and b3. System.out.println( str1 ); System.out.println( str2 ); System.out.println( str3 ); } }
Teste agora

Saída: 

 The character 1 is a letter: false The character ) is a letter: false The character * is a letter: false

Método Java Character isLetter (int codePoint)

O método isLetter(int codePoint) da classe de caracteres determina se o caractere fornecido (ou especificado) é uma letra ou não.

Um caractere é considerado uma letra se o tipo de categoria geral fornecido pelo Character.getType(codePoint) for um dos seguintes:

  • LETRA MAIÚSCULA.
  • LETRA MINÚSCULA.
  • TITLECASE_LETTER.
  • MODIFICADOR_LETTER.
  • OTHER_LETTER

Sintaxe

 public static boolean isLetter(int codePoint)

Parâmetro

O método acima requer apenas um parâmetro:

a.)O codePoint que é o caractere que precisa ser testado.

Valor de retorno

O método isLetter(int codePoint) retorna um valor booleano, ou seja, verdadeiro, se o caractere fornecido (ou especificado) for uma letra. Caso contrário, o método retornará falso.

Exemplo 4

 public class JavaCharacterisLetterExample4 { public static void main(String[] args) { // Create four char primitives ch1, ch2, ch3 and ch4. int codePoint1; int codePoint2; int codePoint3; int codePoint4; // Assign the values to ch1, ch2, ch3 and ch4. codePoint1 = 56; codePoint2 = 110; codePoint3= 123; codePoint4 = 315; // Create four boolean primitives b1, b2, b3 and b4; boolean b1, b2, b3, and b4; // Check whether ch1, ch2, ch3 and ch4 are letters or not and assign the result to b1, b2, b3 and b4. b1 = Character.isLetter(codePoint1); b2 = Character.isLetter(codePoint2); b3 = Character.isLetter(codePoint3); b4 = Character.isLetter(codePoint4); String str1 = 'The first codePoint '+codePoint1 + ' is a letter: ' + b1; String str2 = 'The second codePoint '+codePoint2 + ' is a letter: ' + b2; String str3 = 'The third codePoint '+codePoint3 + ' is a letter: ' + b3; String str4 = 'The fourth codePoint '+codePoint4 + ' is a letter: ' + b3; // Print the values of b1, b2, b3 and b4. System.out.println(str1); System.out.println(str2); System.out.println(str3); System.out.println(str4); } }
Teste agora

Saída: 

 The first codePoint 56 is a letter: false The second codePoint 110 is a letter: true The third codePoint 123 is a letter: false The fourth codePoint 315 is a letter: false

Exemplo 5

 import java.util.Scanner; public class JavaCharacterisLetterExample5 { public static void main(String[] args) { // Ask for user input System.out.print('Enter the first input:'); // Use the Scanner class to get the user input Scanner s1 = new Scanner(System.in); // Gets the user input char[] value1 = s1.nextLine().toCharArray(); // Check whether the user input is a letter or not. for (char ch1 : value1) { boolean result1 = Character.isLetter(ch1); // print the result if(result1){ System.out.println('The character '' + ch1 + '' is a letter. '); } else{ System.out.println('The character '' + ch1 + '' is not a letter.'); } System.out.print('Enter the second input:'); Scanner s2 = new Scanner(System.in); char[] value2 = s2.nextLine().toCharArray(); for (char ch2 : value2) { boolean result2 = Character.isLetter(ch2); if(result2){ System.out.println('The character '' + ch2 + '' is a letter. '); } else{ System.out.println('The character '' + ch2 + '' is not a letter.'); } System.out.print('Enter the third input:'); Scanner s3 = new Scanner(System.in); char[] value3 = s3.nextLine().toCharArray(); for (char ch3 : value3) { boolean result3 = Character.isLetter(ch3); if(result2){ System.out.println('The character '' + ch3 + '' is a letter. '); } else{ System.out.println('The character '' + ch3 + '' is not a letter.'); } } } } } }

Saída: 

 Enter the first input:8 The character '8' is not a letter. Enter the second input:T The character 'T' is a letter. Enter the third input:& The character '&' is a letter.