Get Second to last character position from string

Question

I have a dynamically formed string like - part1.abc.part2.abc.part3.abc

In this string I want to know position of second to last \".\" so that i can split string as

Answer 1

You can use the String.LastIndexOf('.') method to get the position of the last full-stop/period, then use that position in a second call to LastIndexOf('.') to get the last but one, e.g.:

string aString = "part1.abc.part2.abc.part3.abc";
int lastPos = aString.LastIndexOf('.');

int lastPosButOne = aString.LastIndexOf('.', lastPos - 1);

But I'd recommend using String.Split('.') which will give you an array of the string parts, then you can take the last but one, e.g.

string aString = "part1.abc.part2.abc.part3.abc";
string[] parts = aString.Split('.');

string lastPartButOne = parts[parts.Length - 1];