- 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() methodÂÂimportjava.util.*;importjava.lang.*;ÂÂpublicclassGFG {   Âpublicstaticvoidmain(String[] args)   Â{       Â// two characters       Âcharc1 ='A', c2 ='4';       Â// Function to check if the character       Â// is digit or not       ÂSystem.out.println(           Âc1 +" is a digit -> "           Â+ Character.isDigit(c1));       ÂSystem.out.println(           Âc2 +" is a digit -> "           Â+ Character.isDigit(c2));   Â}}Output:A is a digit -> false 4 is a digit -> true
Program 2:
// Java program to illustrate the// Character.isDigit() methodÂÂimportjava.util.*;importjava.lang.*;ÂÂpublicclassGFG {   Âpublicstaticintsearch_digit(String s)   Â{       Â// Function to check if is digit       Â// is found or not       Âfor(inti =0; i < s.length(); i++) {           Âif(Character.isDigit(                   Âs.charAt(i))               Â==true) {               Â// return position of digit               Âreturni +1;           Â}       Â}       Â// return 0 if digit not present       Âreturn0;   Â}   Âpublicstaticvoidmain(String[] args)   Â{       Â// Array of strings       ÂString[] arr = {"ABC4DEF","QWERTY"};       Â// To store the position of digit       Âintindex =0;       Â// Traverse the array arr[] to find digit       Â// within it's elements       Âfor(String x : arr) {           Âindex = search_digit(x);           Âif(index !=0) {               ÂSystem.out.println(                   Â"Digit found at : "                   Â+ (index)                   Â+"th position.");           Â}           Âelse{               ÂSystem.out.println(                   Â"Digit not present.");           Â}       Â}   Â}}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.*;ÂÂpublicclassGFG {   Âpublicstaticvoidmain(String[] args)   Â{       Â// create codePoints       Âintcp1 =57;       Âintcp2 =84;       Â// Check whether the codePoints       Â// are digit or not.       ÂSystem.out.println(           Â"The codePoint cp1 is a digit -> "           Â+ Character.isDigit(cp1));       ÂSystem.out.println(           Â"The codePoint cp2 is a digit -> "           Â+ Character.isDigit(cp2));   Â}}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.*;ÂÂpublicclassMain {   Âpublicstaticvoidmain(String[] args)   Â{       Â// create codePoints       Âintcp1 =0x50;       Âintcp2 =0x06f8;       Â// Check whether the codePoints       Â// are digit or not.       ÂSystem.out.println(           Â"The codePoint cp1 is a digit -> "           Â+ Character.isDigit(cp1));       ÂSystem.out.println(           Â"The codePoint cp2 is a digit -> "           Â+ Character.isDigit(cp2));   Â}}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-
Character isDigit() method in Java with examples
