find digits before first space in string?

[BonaDrag]

I have a string that looks like this:
[ID] [LastName], [FirstName]
I want to fetch the ID, it consists of one or more digits. I'm guessing I have to find the first space of the string and then fetch the digit(s) before that space. If I understand things correctly I can't use Substring or IndexOf for this.

Any ideas on how to solve this? As always - I'm thankful for any help!

[ddanbe]

Try this out:

static void Main()
    {
        string str = "   123 Lname Fname";
        char[] strToParse = str.ToCharArray(); // convert string to array of chars
        char ch;
        int charpos = 0;    
        do          //skip whitespace except '\n'            
        {
            ch = strToParse[charpos]; 
            charpos++;            
        }            
        while (ch != '\n' && char.IsWhiteSpace(ch));
        charpos--; //Putback a char
        Console.WriteLine(strToParse[charpos]); // this will print the first digit of your ID: 1 in this case
        Console.ReadKey();       
    }

I just reworked some code from this snippet: http://www.daniweb.com/code/snippet217185.html

[BonaDrag]

Thanks, ddanbe! I'm not sure I understand every line of the code, I mostly speak "newbie" :) I want every digit of the ID that's before the first space. What do I need to change in the code above to achieve that?

[ddanbe]

Well, you can find that in the snippet I gave you. I know it is perhaps somewhat above "newbie" level, but give it a try. Look at the lines between 131 and 171. If you cannot figure it out, please feel free to tell so. I or other people around here will be most happy to help you out:)

[Momerath]

int myNumber = Int32.Parse(str.Trim().Substring(0, str.Trim().IndexOf(' ')));

This will attempt to convert the first text of the string into an integer. Leading spaces are ignored. If you know you don't have leading spaces, remove the Trim() calls.

[BonaDrag]

ddanbe: I wasn't able to figure out your example, and to be honest it seems like an awful lot of code for a small function :) Thanks anyway!

Momerath: That's more along the lines of how I like to write code. I was obviously very wrong in my first post about Substring and IndexOf :) My thought was to loop through the string until I hit the blank space, count how many digits I had passed and use that number as an index. Your's is much better, thanks!