Single

Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists.

Syntax

Single<TSource>([predicate])

Parameters

predicate

A function to test an element for a condition: Boolean predicate(TSource)

Return Value

The single element of the input sequence that satisfies a condition.

Remarks

The Single method throws an exception if the input sequence contains no matching element. To instead return null when no matching element is found, use SingleOrDefault.