We have seen operators like map and filter in previous examples. They are basically used to perform a specific operation on the stream of data and return new Observable to form an Observable chain. Operators themselves are Observers to the Observable they are called on.

RxJava has a rich set of operators used to perform various operations with the following categories:

• Creating observables: The set of operators used to create new Observable.
• Transforming observables: Operators used to transform items emitted by observables they called upon.
• Filtering observable: Operators used to emit selective data.
• Combining observable: Used to combine multiple source observables to form a single Observable.
• Error handling: Operators that are used to recover from the error condition notified from Observable.
• Utility Operator: Used to perform some miscellaneous operations with Observable.
• Conditional and Boolean operators: Used to evaluate one or more Observable or even emitted items.
• Mathematical and aggregate: Operators used to perform various operations on the entire sequence of emitted data.

It is good to visit: http://reactivex.io/documentation/operators.html, to get full details about each of the operators, instead of having details listed here.