Question: I am looking to extract ranges from an list of integers using linq:

for example I am looking to split the following list: 

```
List<int> numberList = new List<int>() { 30, 60, 90, 120, 150, 180, 270, 300, 330 };  

```

into a list of integer ranges that will look like:

```
{ 30, 180 }
{ 270, 330 }

```

ie: where the next seq is greater than 30

another example : 

```
List<int> numberList = new List<int>() { 30, 60, 120, 150, 270, 300, 330 };  

```

into a list of integer ranges that will look like:

```
{ 30, 60 }
{ 120, 150 }
{ 270, 330 }

```

I have tried with for loops to find the best way possible however I don't
know where to start trying to use a linq query to do this.

Answer: 
You could write a method to handle the split:

```
IEnumerable<IList<int>> SplitValues(IList<int> input, int difference = 30)
{
    List<int> results = new List<int>();
    int last = input.First();
    foreach(var value in input)
    {
        if (value - last > difference)
        {
            yield return new[] {results.First(), results.Last()};
            results = new List<int>();
        }

        results.Add(value);
        last = value;
    }

    yield return new[] {results.First(), results.Last()};
}

```

This matches your specifications as described, returning:

```
{ 30, 60 }
{ 120, 150 }
{ 270, 330 }

```

Note that a single value within the collection without a range will be duplicated. For example, `{ 30, 120, 150 }` will return:

```
{ 30, 30 }
{ 120, 150 }

```
You must use LINQ? If not, what about:

```
List<int> numberList = new List<int>() { 30, 60, 120, 150, 270, 300, 330 };  

Dictionary<int, int> result = new Dictionary<int, int>();
int lastStart = numberList.First();
for(int i=1; i < numberList.Count; i++)
{
    if(numberList[i] >= lastStart + 30)
    {
        result.Add(lastStart, numberList[i]);
        if (i == numberList.Count - 1) break;
        lastStart = numberList[i + 1];
        i++;
    }
}

foreach (var item in result)
{
    Console.WriteLine("{{{0}, {1}}}", item.Key, item.Value);
}

```