c# 如何获得具有多个相同字符的 substring

Question

I have the following string, with the variable of s :

Room: 501, User: John, Model: XPR500 Serial: JK0192, Condition: Good

I want to extract the Model, XPR500 and the Serial, JK0192

I was able to get the model with the following code:

                int pFrom = s.IndexOf("Model: ") + "Model: ".Length;
                int pTo = s.LastIndexOf(" Serial:");

                String model = s.Substring(pFrom, pTo - pFrom);

But, I am having difficulty getting the serial value. I have attempted this code:

                int pFromt = s.IndexOf("Serial: ") + "Serial: ".Length;
                int pToT = s.LastIndexOf(", ");

                string serial = s.Substring(pFromt, pToT - pFromt);

but it returns

JK0192,Condition: Good

I am having trouble getting it to get everything from Serial: and the next comma.

Can anyone see where I am going wrong?

Answer 1

You can try to use a simple regex:

@"Model\:\s([\w\d]*).*Serial\:\s([\w\d]*).*"

Here is a full example:

using System;
using System.Text.RegularExpressions;

public class Example
{
    public static void Main()
    {
        string pattern = @"Model\:\s([\w\d]*).*Serial\:\s([\w\d]*).*";
        string input = @"Room: 501, User: John, Model: XPR500   Serial: JK0192, Condition: Good";
        RegexOptions options = RegexOptions.Multiline;

        foreach (Match m in Regex.Matches(input, pattern, options))
        {
            Console.WriteLine("'{0}' found at index {1}.", m.Value, m.Index);
        }
    }
}

Hope this will help

Answer 2

You can use an array of string delimiters. I would use the titles as delimiters. I wouldn't use comma because:

1. Comma is not always a delimiter
2. You will still need to remove the titles

Here is some code you can try. It uses String.Split instead of solely searching strings manually and parsing substrings

static void Main(string[] args)
{
    var s = "Room: 501, User: John, Model: XPR500   Serial: JK0192, Condition: Good";
    s = s.Replace(",", ""); // first, remove all the commas
    var delimiters = new string[] { "Room:", "User:", "Model:", "Serial:", "Condition:" };
    // use a function which doesn't assume the order or inclusion of all the delimiters
    model = getValue(s, delimiters, "Model:");
    serial = getValue(s, delimiters, "Serial:");
    Console.WriteLine($"Model = '{model}'");
    Console.WriteLine($"Serial = '{serial}'");
    Console.ReadLine();
}

private static string getValue(string s, string[] delimiters, string delimiter)
{
    // find the index of the beginning of the rest of the string after your sought title
    var index = s.IndexOf(delimiter) + delimiter.Length;
    // split the rest of the string by all the delimiters, take the first item
    return s.Substring(index).Split(delimiters, StringSplitOptions.RemoveEmptyEntries).First().Trim();
}