c# - How to efficiently limit and then concatenate a result with a linq / lambda expression? -

c# - How to efficiently limit and then concatenate a result with a linq / lambda expression? -

i in process of creating service create easy user select protocol iana - protocol registry.

as might imagine searching registry term http pulls lot of hits. since amt-soap-http going selected user much less straight http decided thought pull out starts http , concatenate remaining results.

the below lambda look result of thought process:

var records = this._ianaregistryservice.getalllike(term).tolist(); var results = records.where(r => r.name.startswith(term)) .orderby(r => r.name) .concat(records.where(r => !r.name.startswith(term)) .orderby(r => r.name)) .take(maxresultsize);

unfortunately, sense iterating through results more times necessary. premature optimization considerations aside there combination of lambda expressions more efficient above?

it might more efficient two-step ordering:

var results = records.orderby(r => r.name.startswith(term) ? 1 : 2) .thenby(r => r.name) .take(maxresultsize);

c# lambda concat