Qfyilyi

I'm having trouble getting the first item from a list. The data is added to the list from a text file however, the system is returning System.Linq.Enumerable+<TakeIterator>d__25'1[System.String] instead of the first item in the list.

The following is my implementation

string inputData = rawInputData.Split(',');

List<string> splitData = new List<string>(inputData.Length);

splitData.AddRange(inputData);

var numberOfCaves = splitData.Take(1);

Console.Write(numberOfCaves);

I am unsure as why this is happening and any suggestions would be appreciated, Thanks!

Just use FirstOrDefault.

You can also save yourself a lot of footwork, as Split returns an array (IEnumerable) already. So you don't have to create a new list and add it

The problem is essentially, Take Returns an IEnumerable (a list for all intents and purposes, that hasn't been traversed yet), Console.WriteLine doesn't know how to convert it to a string implicitly so it writes its type name

var result = rawInputData.Split(',').FirstOrDefault();



if(result == null) // checks if there are no elements and results null

  Console.WriteLine("darn");

else    

  Console.WriteLine(result);

Additional Resources

Enumerable.FirstOrDefault Method

Returns the first element of a sequence, or a default value if no
element is found.

String.Split Method

Returns a string array that contains the substrings in this instance
that are delimited by elements of a specified string or Unicode
character array.

Enumerable.Take(IEnumerable, Int32) Method

Returns a specified number of contiguous elements from the start of a
sequence.

• 
  Returns IEnumerable<TSource> An IEnumerable that contains the specified number of elements from the start of the input sequence.

Enumerable Class

• The methods in this class provide an implementation of the standard query operators for querying data sources that implement
  IEnumerable. The standard query operators are general purpose
  methods that follow the LINQ pattern and enable you to express
  traversal, filter, and projection operations over data in any
  .NET-based programming language.




• The majority of the methods in this class are defined as extension methods that extend IEnumerable. This means they can be called like
  an instance method on any object that implements IEnumerable.




• Methods that are used in a query that returns a sequence of values do not consume the target data until the query object is enumerated.
  This is known as deferred execution. Methods that are used in a query
  that returns a singleton value execute and consume the target data
  immediately.

Update

As a side note, result can never be null here. – Antonín Lejsek

Which is indeed correct

string.Split Will return at least 1 element

Use First or FirstOrDefault instead. These eagerly get the first item. Take uses deferred execution, so what you are actually printing is the ToString() of the iterator, not the value of the first item.

The best clue when you experience these kind of issues with LINQ is that you should assume that anything returning IEnumerable<T> is deferred (not always true though) and that anything returning a single item is eager (e.g. Max, First, Last, Single, and so on).

Aside of First or FirstOrDefault you can also directly access the array entries.

string inputData = rawInputData.Split(',');

string first = inputData[0];

string second = inputData[1];

...

But you have to make sure that the array index you access really exists. Otherwise you get an Exception for accessing non existent entry.