How to check if IEnumerable is null or empty?

Question

I love string.IsNullOrEmpty method. I\'d love to have something that would allow the same functionality for IEnumerable. Is there such? Maybe some collection he

Answer 1

 public static bool AnyNotNull<TSource>(this IEnumerable<TSource> source)
    {
        return source != null && source.Any();
    }

my own extension method to check Not null and Any

Answer 2

Jon Skeet's anwser (https://stackoverflow.com/a/28904021/8207463) has a good approach using Extension Method - Any() for NULL and EMPTY. BUT he´s validating the questions´owner in case for NOT NULL. So carefully change Jon´s approach to validate AS NULL to:

If (yourList?.Any() != true) 
{
     ..your code...
}

DO NOT use ( will not validate AS NULL):

If (yourList?.Any() == false) 
{
     ..your code...
}

You can also in case validating AS NOT NULL ( NOT tested just as example but without compiler error) do something like using predicate :

If (yourList?.Any(p => p.anyItem == null) == true) 
{
     ..your code...
}

https://referencesource.microsoft.com/#System.Core/System/Linq/Enumerable.cs,8788153112b7ffd0

For which .NET version you can use it please check:

https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.any?view=netframework-4.8#moniker-applies-to

Answer 3

if (collection?.Any() == true){
    // if collection contains more than one item
}
if (collection?.Any() != true){
    // if collection is null
    // if collection does not contain any item
}

Answer 4

Another way would be to get the Enumerator and call the MoveNext() method to see if there are any items:

if (mylist != null && mylist.GetEnumerator().MoveNext())
{
    // The list is not null or empty
}

This works for IEnumerable as well as IEnumerable<T>.

Answer 5

The other best solution as below to check empty or not ?

for(var item in listEnumerable)
{
 var count=item.Length;
  if(count>0)
  {
         // not empty or null
   }
  else
  {
       // empty
  }
}

Answer 6

public static bool IsNullOrEmpty<T>(this IEnumerable<T> enumerable) {
    return enumerable == null || !enumerable.Any();
}