Il metodo isLetter(char ch) della classe Character determina se il carattere dato (o specificato) è una lettera o meno.

Un carattere è considerato una lettera se il tipo di categoria generale fornito da Character.getType(ch) è uno dei seguenti:

• LETTERA MAIUSCOLA.
• LETTERA MINUSCOLA.
• TITLECASE_LETTER.
• LETTERA_MODIFICATORE.
• ALTRA_LETTERA

Sintassi

 public static boolean isLetter(char ch) 

Parametro

cap : È il carattere che deve essere messo alla prova.

Valore di ritorno

Il metodo isLetter(char ch) restituisce un valore booleano, ovvero true se il carattere fornito (o specificato) è una lettera. Altrimenti il ​​metodo restituisce false.

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Esempio 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 ); } } 

Produzione:

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

Esempio 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 ); } } 

Produzione:

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

Esempio 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 ); } } 

Produzione:

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

Metodo Java Character isLetter(int codePoint).

Il metodo isLetter(int codePoint) della classe di caratteri determina se il carattere dato (o specificato) è una lettera o meno.

Un carattere è considerato una lettera se il tipo di categoria generale fornito da Character.getType(codePoint) è uno dei seguenti:

• LETTERA MAIUSCOLA.
• LETTERA MINUSCOLA.
• TITLECASE_LETTER.
• LETTERA_MODIFICATORE.
• ALTRA_LETTERA

Sintassi

 public static boolean isLetter(int codePoint) 

Parametro

Il metodo sopra richiede un solo parametro:

a.) Il codePoint che è il carattere che deve essere testato.

Valore di ritorno

Il metodo isLetter(int codePoint) restituisce un valore booleano, ovvero true, se il carattere fornito (o specificato) è una lettera. Altrimenti il ​​metodo restituisce false.

Esempio 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); } } 

Produzione:

data da stringere

 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 

Esempio 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.'); } } } } } } 

Produzione:

 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.