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C# Linq FirstorDefault Method
Use the FirstorDefault() method to return the first element of a sequence or a default value if element isn’t there.
The following is our empty list −
List<double> val = new List<double> { };
Now, we cannot display the first element, since it is an empty collection. For that, use the FirstorDefault() method to display the default value.
val.AsQueryable().FirstOrDefault();
The following is the complete example.
Example
using System; using System.Collections.Generic; using System.Linq; class Demo { static void Main() { List<double> val = new List<double> { }; double d = val.AsQueryable().FirstOrDefault(); Console.WriteLine("Default Value = "+d); if (d == 0.0D) { d = 0.1D; } Console.WriteLine("Default Value changed = "+d); } }
Output
Default Value = 0 Default Value changed = 0.1
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