Character isDigit() method in Java with examples
- The java.lang.Character.isDigit(char ch) is an inbuilt method in java which determines whether a specified character is a digit or not. There are few conditions that a character must accomplish to be accepted as a digit. That is if the general category type of a character, provided by Character.getType(ch), is DECIMAL_DIGIT_NUMBER, then the character is a digit.
Some Unicode character ranges that contain digits:
From ‘\u0030’ to ‘\u0039’ : ISO-LATIN-1 digits (‘0’ through ‘9’)
From ‘\u0660’ to ‘\u0669’ : Arabic-Indic digits
From ‘\u06F0’ to ‘\u06F9’ : Extended Arabic-Indic digits
From ‘\u0966’ to ‘\u096F’ : Devanagari digits
From ‘\uFF10’ to ‘\uFF19’ : Fullwidth digitsApart from the above mentioned ranges, many other character ranges contain digits as well.
Syntax:
public static boolean isDigit(char ch)
Parameter: This method accepts character parameter ch as an argument, which is to be tested.
Return value:This method returns a boolean value. It returns True if ch is digit, else False.
Note: This method cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the isDigit(int) method.
Below programs illustrate the above method:
Program 1:// Java program to illustrate the// Character.isDigit() methodimportjava.util.*;importjava.lang.*;publicclassGFG {publicstaticvoidmain(String[] args){// two characterscharc1 ='A', c2 ='4';// Function to check if the character// is digit or notSystem.out.println(c1 +" is a digit -> "+ Character.isDigit(c1));System.out.println(c2 +" is a digit -> "+ Character.isDigit(c2));}}Output:A is a digit -> false 4 is a digit -> true
Program 2:
// Java program to illustrate the// Character.isDigit() methodimportjava.util.*;importjava.lang.*;publicclassGFG {publicstaticintsearch_digit(String s){// Function to check if is digit// is found or notfor(inti =0; i < s.length(); i++) {if(Character.isDigit(s.charAt(i))==true) {// return position of digitreturni +1;}}// return 0 if digit not presentreturn0;}publicstaticvoidmain(String[] args){// Array of stringsString[] arr = {"ABC4DEF","QWERTY"};// To store the position of digitintindex =0;// Traverse the array arr[] to find digit// within it's elementsfor(String x : arr) {index = search_digit(x);if(index !=0) {System.out.println("Digit found at : "+ (index)+"th position.");}else{System.out.println("Digit not present.");}}}}Output:Digit found at : 4th position. Digit not present.
- The java.lang.Character.isDigit(int codePoint) is an inbuilt method in java which determines whether the specified Unicode code point character of integer type is a digit or not.
There are few conditions that a character must accomplish to be accepted as a digit. That is if the general category type of a character, provided by getType(codepoint), is a DECIMAL_DIGIT_NUMBER, then the character is a digit. Some Unicode character ranges that contain digits:
From ‘\u0030’ to ‘\u0039’ : ISO-LATIN-1 digits (‘0’ through ‘9’)
From ‘\u0660’ to ‘\u0669’ : Arabic-Indic digits
From ‘\u06F0’ to ‘\u06F9’ : Extended Arabic-Indic digits
From ‘\u0966’ to ‘\u096F’ : Devanagari digits
From ‘\uFF10’ to ‘\uFF19’ : Fullwidth digitsApart from the above mentioned ranges, many other character ranges contain digits as well.
Syntax:
public static boolean isDigit(int codePoint)
Parameter: This method accepts unicode character parameter codePoint of integer type as an argument, which is to be tested.
Return value: This method returns a boolean value. It returns True if the specified character is digit, else it returns False.
Below programs illustrate the above method:
Program 1:// This program demonstrates the use of// isDigit(int codePoint) method of Character class.importjava.util.*;publicclassGFG {publicstaticvoidmain(String[] args){// create codePointsintcp1 =57;intcp2 =84;// Check whether the codePoints// are digit or not.System.out.println("The codePoint cp1 is a digit -> "+ Character.isDigit(cp1));System.out.println("The codePoint cp2 is a digit -> "+ Character.isDigit(cp2));}}Output:The codePoint cp1 is a digit -> true The codePoint cp2 is a digit -> false
Program 2:
// This program demonstrates the use of// isDigit(int codePoint) method of// Character class.importjava.util.*;publicclassMain {publicstaticvoidmain(String[] args){// create codePointsintcp1 =0x50;intcp2 =0x06f8;// Check whether the codePoints// are digit or not.System.out.println("The codePoint cp1 is a digit -> "+ Character.isDigit(cp1));System.out.println("The codePoint cp2 is a digit -> "+ Character.isDigit(cp2));}}Output:The codePoint cp1 is a digit -> false The codePoint cp2 is a digit -> true
Reference: https://docs.oracle.com/javase/8/docs/api/java/lang/Character.html#isDigit-char-
