Metoda isLetter(char ch) třídy Character určuje, zda daný (nebo zadaný) znak je nebo není písmeno.

Znak je považován za písmeno, pokud je obecný typ kategorie poskytovaný pomocí Character.getType(ch) jedním z následujících:

• VELKÉ PÍSMENO.
• MALÝM PÍSMEM.
• TITLECASE_LETTER.
• MODIFIER_LETTER.
• OTHER_LETTER

Syntax

 public static boolean isLetter(char ch) 

Parametr

ch : Je to postava, kterou je třeba otestovat.

Návratová hodnota

Metoda isLetter(char ch) vrací booleovskou hodnotu, tj. true, pokud je daný (nebo zadaný) znak písmeno. Jinak metoda vrací false.

Příklad 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 ); } } 

Výstup:

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

Příklad 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 ); } } 

Výstup:

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

Příklad 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 ); } } 

Výstup:

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

Metoda znak Java isLetter(int codePoint).

Metoda isLetter(int codePoint) znakové třídy určuje, zda daný (nebo zadaný) znak je nebo není písmeno.

Znak je považován za písmeno, pokud je obecný typ kategorie poskytovaný pomocí Character.getType(codePoint) jedním z následujících:

• VELKÉ PÍSMENO.
• MALÝM PÍSMEM.
• TITLECASE_LETTER.
• MODIFIER_LETTER.
• OTHER_LETTER

Syntax

 public static boolean isLetter(int codePoint) 

Parametr

Výše uvedená metoda vyžaduje pouze jeden parametr:

a.) CodePoint, což je znak, který je třeba otestovat.

Návratová hodnota

Metoda isLetter(int codePoint) vrací booleovskou hodnotu, tj. true, pokud je daný (nebo zadaný) znak písmeno. Jinak metoda vrací false.

Příklad 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); } } 

Výstup:

 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 

Příklad 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.'); } } } } } } 

Výstup:

 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.