Match whole numbers

Question

What could be the regular expression to replace whole numbers in a textfile?

For example

I want to replace 7 with 7.59 but not 167 with 167.59 

Any ideas?

Answer 1

Try this:

string input = "7,167,5.5 1, 1.5, 23, 1,000";
string pattern = @"\b(?<!\.)(\d)(?![.,])\b";
string result = Regex.Replace(input, pattern, "$1.59");
Console.WriteLine("Original: {0}", input);
Console.WriteLine("Result: {0}", result);

The "$1" in the replacement pattern refers to the captured group value. The ".59" is appended to give the result you described.

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Answer 2

Hi


Apologies but the numbers I want to match are in the following form 

 \clock [t= 7] ( I want to match only 7)
\clock [t= 177] (but not 177)  

Answer 3

The pattern for the number portion is still the same, but to restrict it to the above types of text you could do this:

string[] inputs = { @"\clock [t= 7]", @"\clock [t= 177]" };
string pattern = @"(?<start>\\clock\s+\[t=\s*)\b(?<!\.)(?<value>\d)(?![.,])\b(?<end>])";
foreach (string input in inputs)
{
	Match m = Regex.Match(input, pattern);
	if (m.Success)
	{
		string value = m.Groups["value"].Value;
		Console.WriteLine("Value: {0}", value);
	}

	string result = Regex.Replace(input, pattern, "${start}${value}.59${end}");
	Console.WriteLine("Original: {0}", input);
	Console.WriteLine("Result: {0}", result);
}

I switched to named groups for clarity in the replacement pattern.

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