Question

Hi how do you extract multiple decimals with different number of decimal places from a string?
I’m looking to find a generic way to extract 3 numbers out the following strings.

e.g

CC77X1722X12 => 77,1722,12
PC77.5X10102X12.5 => 77.5, 10102, 12.5
XP60.25X0.333X12 => 60.25, 0.333, 12

The three numbers are always separated by ‘X’, and the string always starts with 2 characters

Thanks!

Answer 1

Since you have such a specific pattern, you don’t even need to use regular expressions. Because the first two characters can be ignored and all the numbers are separated by ‘X’ characters, this C# code should do the trick (with appropriate error handling added, of course)

public IEnumerable<decimal> ExtractNumbers(string s)
{                                                  // For s = "CC77X1722X12"
    string[] nums = s.Substring(2).Split('X');     // nums = ["77", "1722", "12"];
    return nums.Select(num => decimal.Parse(num)); // returns [77, 1722, 12]
}

For production code, though, I would recommend decimal.TryParse over decimal.Parse. To use that method, you could write something like

public IEnumerable<decimal> ExtractNumbers(string s)
{
    string[] nums = s.Substring(2).Split('X');
    return nums
        .Select(num => {
                decimal d;
                if (decimal.Parse(num, out d))
                    return new {Number = d, Succeeded = true};
                return new {Number = 0, Succeeded = false};
            })
        .Filter(result => result.Succeeded)
        .Select(result => result.Number);
}