Operators that originate new Observables.

• Create — create an Observable from scratch by calling observer methods programmatically
• Defer — do not create the Observable until the observer subscribes, and create a fresh Observable for each observer
• Empty/Never/Throw — create Observables that have very precise and limited behavior
• From — convert some other object or data structure into an Observable
• Interval — create an Observable that emits a sequence of integers spaced by a particular time interval
• Just — convert an object or a set of objects into an Observable that emits that or those objects
• Range — create an Observable that emits a range of sequential integers
• Repeat — create an Observable that emits a particular item or sequence of items repeatedly
• Start — create an Observable that emits the return value of a function
• Timer — create an Observable that emits a single item after a given delay

Create (생성)

create an Observable from scratch by means of a function

함수를 사용하여 처음부터 Observable 생성

You can create an Observable from scratch by using the Create operator. You pass this operator a function that accepts the observer as its parameter. Write this function so that it behaves as an Observable — by calling the observer’s onNext, onError, and onCompleted methods appropriately.