func startsWith<S0 : SequenceType, S1 : SequenceType where S0.Generator.Element == S0.Generator.Element, S0.Generator.Element : Equatable>(_: S0, prefix: S1) Return true iff the the initial elements of s are equal to prefix. Declaration func startsWith<S0 : SequenceType, S1 : SequenceType where S0.Generator.Element == S0.Generator.Element, S0.Generator.Element : Equatable>(s: S0, prefix: S1) -> Bool func startsWith<S0 : SequenceType, S1 : SequenceType where S0.Generator.Element == S0.Generator.Element>(_: S0, prefix: S1, isEquivalent: @noescape (S0.Generator.Element, S0.Generator.Element) -> Bool) Return true iff s begins with elements equivalent to those of prefix, using isEquivalent as the equivalence test. Requires: isEquivalent is an equivalence relation Declaration func startsWith<S0 : SequenceType, S1 : SequenceType where S0.Generator.Element == S0.Generator.Element>(s: S0, prefix: S1, isEquivalent: @noescape (S0.Generator.Element, S0.Generator.Element) -> Bool) -> Bool