This section explains operators with which you conditionally emit or transform Observables, or can do boolean evaluations of them:

• amb( ) — given two or more source Observables, emits all of the items from the first of these Observables to emit an item
• defaultIfEmpty( ) — emit items from the source Observable, or emit a default item if the source Observable completes after emitting no items
• (rxjava-computation-expressions) doWhile( ) — emit the source Observable's sequence, and then repeat the sequence as long as a condition remains true
• (rxjava-computation-expressions) ifThen( ) — only emit the source Observable's sequence if a condition is true, otherwise emit an empty or default sequence
• skipUntil( ) — discard items emitted by a source Observable until a second Observable emits an item, then emit the remainder of the source Observable's items
• skipWhile( ) — discard items emitted by an Observable until a specified condition is false, then emit the remainder
• (rxjava-computation-expressions) switchCase( ) — emit the sequence from a particular Observable based on the results of an evaluation
• takeUntil( ) — emits the items from the source Observable until a second Observable emits an item or issues a notification
• takeWhile( ) and takeWhileWithIndex( ) — emit items emitted by an Observable as long as a specified condition is true, then skip the remainder
• (rxjava-computation-expressions) whileDo( ) — if a condition is true, emit the source Observable's sequence and then repeat the sequence as long as the condition remains true

(rxjava-computation-expressions) — indicates that this operator is currently part of the optional rxjava-computation-expressions package under rxjava-contrib and is not included with the standard RxJava set of operators

• all( ) — determine whether all items emitted by an Observable meet some criteria
• contains( ) — determine whether an Observable emits a particular item or not
• exists( ) and isEmpty( ) — determine whether an Observable emits any items or not
• sequenceEqual( ) — test the equality of the sequences emitted by two Observables