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[ Extract part of a string between point A and B ]

I am trying to extract something from an email. The general format of the email will always be:

blablablablabllabla hello my friend.

[what I want]

Goodbye my friend blablablabla

Now I did:

                    string.LastIndexOf("hello my friend");
                    string.IndexOf("Goodbye my friend");

This will give me a point before it starts, and a point after it starts. What method can I use for this? I found:

String.Substring(Int32, Int32)

But this only takes the start position.

What can I use?

Answer 1

Substring takes the start index (zero-based) and the number of characters you want to copy.

You'll need to do some math, like this:

string email = "Bla bla hello my friend THIS IS THE STUFF I WANTGoodbye my friend";
int startPos = email.LastIndexOf("hello my friend") + "hello my friend".Length + 1;
int length = email.IndexOf("Goodbye my friend") - startPos;
string sub = email.Substring(startPos, length);

You probably want to put the string constants in a const string.

Answer 2

you can also use Regex

string s =  Regex.Match(yourinput,
                        @"hello my friend(.+)Goodbye my friend", 

Answer 3

You can simply calculate the length from the start and end

const string startText = "hello my friend";
var start = str.LastIndexOf(startText) + startText.Length;
var end = str.IndexOf("Goodbye my friend");
var length = end -start;

Answer 4

string s1 = "find a string between within a lengthy string";
string s2 = s1.IndexOf("between").ToString();
string output = s1.Substring(0, int.Parse(s2));
Console.WriteLine("string before between is : {0}", output);