how to extract substring from a undefined length of string?

Substring these string:-

1. ZZ111122
2. ZZZZ222111
3. ZZZZZZZ333
4. ZZZ111333

I have these kind of strings. This value is always starting with Z. And after Z its always either 1 or 2 or 3. But i dont know the numbe开发者_StackOverflow中文版r of Zs in the string. So how can i extract all Z from the string

I don't know if I understood right. If you have "ZZZZ222111" and want only "222111", do it:

string test = "ZZZZ222111";
test = test.Substring(test.LastIndexOf("Z") + 1);

If you want only "ZZZZ", do it:

string test = "ZZZZ222111";
test = test.Substring(0, test.LastIndexOf("Z"));

Both ways are very simple. No need of loops or regular expressions.

Sounds like you're going to want to use regular expressions for this.

Use String.Trim function:

ZeroZValue = stringValue.Trim('Z');

String test = "ZZ111122";
String zOnly = test.Substring(0, test.IndexOfAny("123".ToCharArray()));

Take advantage of IndexOfAny(). I am assuming you want only Z's left over ("extract all Z from the string").

This is not difficult. I recommend processing the text line by line.

You can loop the string character by character. You can use regular expressions. Or you could use my sscanf() replacement class for C#.

int start = someString.IndexOf("Z");
int end = someString.LastIndexOf("Z");
someString.Substring(start , end - start);