Character isDigit() method in Java with examples - GeeksforGeeks

17 May, 2020
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 digitsFrom ‘\u06F0’ to ‘\u06F9’ : Extended Arabic-Indic digitsFrom ‘\u0966’ to ‘\u096F’ : Devanagari digitsFrom ‘\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() method  import java.util.*;import java.lang.*;  public class GFG {      public static void main(String[] args)    {          // two characters        char c1 = 'A', c2 = '4';          // Function to check if the character        // is digit or not        System.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() method  import java.util.*;import java.lang.*;  public class GFG {      public static int search_digit(String s)    {          // Function to check if is digit        // is found or not        for (int i = 0; i < s.length(); i++) {            if (Character.isDigit(                    s.charAt(i))                == true) {                // return position of digit                return i + 1;            }        }        // return 0 if digit not present        return 0;    }      public static void main(String[] args)    {          // Array of strings        String[] arr = { "ABC4DEF", "QWERTY" };          // To store the position of digit        int index = 0;          // Traverse the array arr[] to find digit        // within it's elements        for (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 digitsFrom ‘\u06F0’ to ‘\u06F9’ : Extended Arabic-Indic digitsFrom ‘\u0966’ to ‘\u096F’ : Devanagari digitsFrom ‘\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.import java.util.*;  public class GFG {    public static void main(String[] args)    {        // create codePoints        int cp1 = 57;        int cp2 = 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.import java.util.*;  public class Main {    public static void main(String[] args)    {        // create codePoints        int cp1 = 0x50;        int cp2 = 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-
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 digitsFrom ‘\u06F0’ to ‘\u06F9’ : Extended Arabic-Indic digitsFrom ‘\u0966’ to ‘\u096F’ : Devanagari digitsFrom ‘\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() method  import java.util.*;import java.lang.*;  public class GFG {      public static void main(String[] args)    {          // two characters        char c1 = 'A', c2 = '4';          // Function to check if the character        // is digit or not        System.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() method  import java.util.*;import java.lang.*;  public class GFG {      public static int search_digit(String s)    {          // Function to check if is digit        // is found or not        for (int i = 0; i < s.length(); i++) {            if (Character.isDigit(                    s.charAt(i))                == true) {                // return position of digit                return i + 1;            }        }        // return 0 if digit not present        return 0;    }      public static void main(String[] args)    {          // Array of strings        String[] arr = { "ABC4DEF", "QWERTY" };          // To store the position of digit        int index = 0;          // Traverse the array arr[] to find digit        // within it's elements        for (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.

From ‘\u0030’ to ‘\u0039’ : ISO-LATIN-1 digits (‘0’ through ‘9’)From ‘\u0660’ to ‘\u0669’ : Arabic-Indic digitsFrom ‘\u06F0’ to ‘\u06F9’ : Extended Arabic-Indic digitsFrom ‘\u0966’ to ‘\u096F’ : Devanagari digitsFrom ‘\uFF10’ to ‘\uFF19’ : Fullwidth digits
Apart 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() method  import java.util.*;import java.lang.*;  public class GFG {      public static void main(String[] args)    {          // two characters        char c1 = 'A', c2 = '4';          // Function to check if the character        // is digit or not        System.out.println(            c1 + " is a digit -> "            + Character.isDigit(c1));        System.out.println(            c2 + " is a digit -> "            + Character.isDigit(c2));    }}
A is a digit -> false
4 is a digit -> true

Program 2:
// Java program to illustrate the// Character.isDigit() method  import java.util.*;import java.lang.*;  public class GFG {      public static int search_digit(String s)    {          // Function to check if is digit        // is found or not        for (int i = 0; i < s.length(); i++) {            if (Character.isDigit(                    s.charAt(i))                == true) {                // return position of digit                return i + 1;            }        }        // return 0 if digit not present        return 0;    }      public static void main(String[] args)    {          // Array of strings        String[] arr = { "ABC4DEF", "QWERTY" };          // To store the position of digit        int index = 0;          // Traverse the array arr[] to find digit        // within it's elements        for (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.");            }        }    }}
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 digitsFrom ‘\u06F0’ to ‘\u06F9’ : Extended Arabic-Indic digitsFrom ‘\u0966’ to ‘\u096F’ : Devanagari digitsFrom ‘\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.import java.util.*;  public class GFG {    public static void main(String[] args)    {        // create codePoints        int cp1 = 57;        int cp2 = 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.import java.util.*;  public class Main {    public static void main(String[] args)    {        // create codePoints        int cp1 = 0x50;        int cp2 = 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-
From ‘\u0030’ to ‘\u0039’ : ISO-LATIN-1 digits (‘0’ through ‘9’)From ‘\u0660’ to ‘\u0669’ : Arabic-Indic digitsFrom ‘\u06F0’ to ‘\u06F9’ : Extended Arabic-Indic digitsFrom ‘\u0966’ to ‘\u096F’ : Devanagari digitsFrom ‘\uFF10’ to ‘\uFF19’ : Fullwidth digits
Apart 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.import java.util.*;  public class GFG {    public static void main(String[] args)    {        // create codePoints        int cp1 = 57;        int cp2 = 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));    }}
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.import java.util.*;  public class Main {    public static void main(String[] args)    {        // create codePoints        int cp1 = 0x50;        int cp2 = 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));    }}
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-
Java-Functions
Java
Java
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Comments
Old Comments
Initialize an ArrayList in Java
HashMap in Java with Examples
Interfaces in Java
Object Oriented Programming (OOPs) Concept in Java
ArrayList in Java
How to iterate any Map in Java
Multidimensional Arrays in Java
LinkedList in Java
Stack Class in Java
Overriding in Java