Reading a string from one char to another

Question

I have the following string:

FB:77:CB:0B:EC:09{W: 0,623413, X: 0,015374, Y: 0,005306, Z: -0,781723}

I want to read out the values of W,X,Y,Z as a float/decimal. The values are not always the same length.

How can I read this string from one character to another without using relative positions?

Answer 1

I'd suggest matching the "inner" part with a regular expression, but removing the "outer" part manually first - just to keep the regex as simple as possible.

Here's a complete example, with a method that returns the result as a Dictionary<string, string>. It's not clear how you'd then want to convert the sample values you've given (e.g. "0,623413") into integers, but I'd treat that as a separate task from the initial parsing.

I'm assuming that it's fine to strip all trailing commas from values:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

class Test
{
    static void Main()
    {
        string input = "FB:77:CB:0B:EC:09{W: 0,623413, X: 0,015374, Y: 0,005306, Z: -0,781723}";
        var parsed = Parse(input);
        foreach (var entry in parsed)
        {
            Console.WriteLine($"Key = '{entry.Key}', Value = '{entry.Value}'");
        }        
    }

    static readonly Regex regex = new Regex(@"(?<key>[A-Z]+): (?<value>[-\d,]+)");
    static IDictionary<string, string> Parse(string input)
    {
        int openBrace = input.IndexOf('{');
        if (openBrace == -1)
        {
            throw new ArgumentException("Expected input to contain a {");
        }
        if (!input.EndsWith("}"))
        {
            throw new ArgumentException("Expected input to end with }");
        }
        string inner = input.Substring(openBrace + 1, input.Length - openBrace - 2);
        var matches = regex.Matches(inner);
        return matches.Cast<Match>()
            .ToDictionary(match => match.Groups["key"].Value,
                          match => match.Groups["value"].Value.TrimEnd(','));
    }
}

Output:

Key = 'W', Value = '0,623413'
Key = 'X', Value = '0,015374'
Key = 'Y', Value = '0,005306'
Key = 'Z', Value = '-0,781723'

Converting those values to integers may be as simple as removing the commas, trimming leading zeroes, and then using int.Parse - but it really depends on what you want the results to be.