A character can be an alphabet, symbol, etc. In other words, a character can be alphanumeric. In C#, we can use the IsDigit()
method to check if a character is numeric or a digit.
The IsDigit()
method can be used on a single character or on a string. In the case of a string, we have to specify the index position of the character in the string.
IsDigit()
returns true
if the character is a decimal digit; otherwise, it returns false
.
// on character
IsDigit(Char)
// on a string
IsDigit(String, int32)
Char
: The character we want to check.
String
: The string that we want to check to see if any character at index position int32
is a digit.
int32
: The index position of the character in a string we want to check.
In the example below, we create some strings and characters and see if certain characters are decimal digits or not.
// use system using System; // create class class DigitChecker { static void Main() { // create characters char char1 = '5'; char char2 = 'p'; // create strings string str1 = "1234"; string str2 = "hi"; // check characters bool a = Char.IsDigit(char1); bool b = Char.IsDigit(char2); bool c = Char.IsDigit(str1, 2); // position 3 bool d = Char.IsDigit(str2, 0); // position 1 // print out returned values System.Console.WriteLine(a); System.Console.WriteLine(b); System.Console.WriteLine(c); System.Console.WriteLine(d); } }
In the code above, line 17 and line 19 return true
because the value of char1
, which is 5
, is actually a numeric value/digit. str1
has 3
at position 3, which is also a number.
The other lines return false
because the values are not decimal digits.
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