How to use Single() Extension with all Overloads?

Yes, Single() is one extension method which has overloads also how to use these overloads
we will see now


Single Extensions:
public static TSource Single<TSource>(this IEnumerable<TSource> source);
public static TSource Single<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate);
public static TSource SingleOrDefault<TSource>(this IEnumerable<TSource> source);
public static TSource SingleOrDefault<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate);


Single :Returns the one and only occurrence

Ex:

int[] intarr2 = new int[1];

intarr2[0] = 150;

int i = intarr2.Single<int>();

Console.WriteLine(i);--à150

int[] intarr3 = new int[1];  // no value in the array even single returns zero

int i = intarr3.Single<int>();

Console.WriteLine(i);--à0 zero

SingleOrDefault<int>();

--------find value -àreturns value ex:150 same like single<int>();

which is also work for only size of array is 1 one only.

In Case of overloads

          int[] intarr4 = new int[5];

           intarr4[0] = 150;

           intarr4[1] = 80;

           intarr4[2] = 25;

           intarr4[3] = 15;

           intarr4[4] = 14;

            int i = intarr4.Single<int>(x=>x==80);

            Console.WriteLine(i);

            int j = intarr4.SingleOrDefault<int>(y => y == 74);

            Console.WriteLine(j);

            Console.Read();

Here i  is 80 in case of single conditation is matched so returns value of I is 80; 

if not match single<int>(x=>==80) returns error

Incase of SingleOrDefault<int>(y => y == 74); // no 74 in intarr4 array

Condatation is not matched but no error by because default value will returns

Conculsion: incase of

Single<int>()

   Or

SingleOrDefault<Tsource>();--àmenas no overloads requires size of array is 1 only.

Why because if it has more then size 1 it gives [runtime asking which single]error by runtime.So go for overloaded.

Incase of overloads:

intarr4.Single<int>(x=>x==80);---condition matchs returns the value.

Other wise error.

intarr2.SingleOrDefault<int>(y => y == 74);

condition matchs returns the value other wise no error Gives zero[default value).