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How to write Regex for numbers only in C#?
A regular expression is a pattern that could be matched against an input text.
The .Net framework provides a regular expression engine that allows such matching.
A pattern consists of one or more character literals, operators, or constructs.
Here are basic pattern metacharacters used by RegEx −
* = zero or more ? = zero or one ^ = not [] = range
The ^ symbol is used to specify not condition.
the [] brackets if we are to give range values such as 0 - 9 or a-z or A-Z
Example
class Program{
public static void Main(){
string num = "123dh";
Regex regex = new Regex(@"^-?[0-9][0-9,\.]+$");
var res = regex.IsMatch(num);
System.Console.WriteLine(res);
}
}Output
False
Example
class Program{
public static void Main(){
string num = "123";
Regex regex = new Regex(@"^-?[0-9][0-9,\.]+$");
var res = regex.IsMatch(num);
System.Console.WriteLine(res);
}
}Output
True
Example
class Program{
public static void Main(){
string num = "123.67";
Regex regex = new Regex(@"^-?[0-9][0-9,\.]+$");
var res = regex.IsMatch(num);
System.Console.WriteLine(res);
}
}Output
True
Updated on: 25-Sep-2020
2K+ Views
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