C# - Finding a string between two strings

Question

I have a string that looks like this: Value->Value2->Value3->ImportantValue->val.

I would like to extract ImportantValue. I have read other posts concerning this question but none of them works for me. I tried this:

int pFrom = path.IndexOf("->") + "->".Length;
int pTo = path.LastIndexOf("->val");
String result = path.Substring(pFrom, pTo - pFrom);

It returns Value2->Value3->ImportantValue->val because it gives out the string between the first -> and ->val. Any ideas on how I would change the above code so that it returns ImportantValue? Thanks in advance.

EDIT

Sorry, I forgot to specify that ImportantValue is always different. The entire string also changes, meaning it will have more three Values. But the ImportantValue is always the second to last element so I will mark the answer from Paul Kertscher as the right one and upvote the other similar answers.

Does "ImportantValue" have some kind of specific formatting or pattern that you are looking for? Maybe it will always be the same value? — Cheesebaron
– Cheesebaron, Commented Feb 19, 2020 at 13:13
Could you give us a realistic string to work with? It might be easier to identify the important value rather than using the '->' marker — sr28
– sr28, Commented Feb 19, 2020 at 13:20

Paul Kertscher · Accepted Answer · 2020-02-19 14:00:58Z

3

If the ImportantValue is always the second to last element, you could do the following

var stringParts = path.Split(new[]{ "->" }, StringSplitOptions.None);
if(stringParts.Length >= 2)
{
    var importantValue = stringParts[stringParts.Length - 2];
}
else
{
    throw new ArgumentException("Input did not match the expected value");
}

You could also use IEnumerable extensions

var importantValue = path.Split(new[]{ "->" }, StringSplitOptions.None)
                         .Reverse() // reverse the enumerable
                         .Skip(1)   // discard "val"
                         .First();  // return the "ImportantValue"

edited Feb 19, 2020 at 14:00

answered Feb 19, 2020 at 13:14

Paul Kertscher

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Comments

Christos · Accepted Answer · 2020-02-19 13:20:13Z

2

Provided that the string has always the same format, you could use just the Split method, and fetch the previous from the last element of the array returned from Split.

var values = path.Split(new []{"->"}, StringSplitOptions.None);
var importantValue = values[values.Length-2];

Pls check .NET Fiddle

edited Feb 19, 2020 at 13:20

answered Feb 19, 2020 at 13:14

Christos

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Comments

Pavel Anikhouski · Accepted Answer · 2020-02-19 13:21:59Z

2

You can use a Split method for that and access a second item from the end

var str = "Value->Value2->Value3->ImportantValue->val";
var items = str.Split(new []{"->"}, StringSplitOptions.None);
var importantValue = items[items.Length - 2];

C# 8 introduced an new approach for indices, so you can use var importantValue = items[^2]; syntax as well

You also may check a length of resulting array, that it has at least two elements

edited Feb 19, 2020 at 13:21

answered Feb 19, 2020 at 13:15

Pavel Anikhouski

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1 Comment

Rahul Sharma Over a year ago

This is the same answer as @Christos

mip · Accepted Answer · 2020-02-19 13:20:29Z

0

I believe you can use string.split with ">" as your char array and get the array. Once you get the array you should be able to iterate the array and get the required value

answered Feb 19, 2020 at 13:20

mip

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Comments

Dmitrii Bychenko · Accepted Answer · 2020-02-19 13:51:32Z

0

When important value is the 2nd from the end, LastIndexOf instead of IndexOf is a quite natural choice; please, note that since we seach from the end, it's pTo which we compute first.

  string path = "Value->Value2->Value3->ImportantValue->val";

  string delimiter = "->";

  int pTo   = path.LastIndexOf(delimiter);
  int pFrom = pTo >= 0 ? path.LastIndexOf(delimiter, pTo) + delimiter.Length : -1;

  // Either important value or null
  string result = pFrom >= 0 
    ? path.Substring(pFrom, pTo - pFrom) 
    : null; // or throw exception here

edited Feb 19, 2020 at 13:51

answered Feb 19, 2020 at 13:45

Dmitrii Bychenko

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