Count

See also

• Official ReactiveX documentation: Count

Observable.count(predicate=None)

Returns an observable sequence containing a value that represents how many elements in the specified observable sequence satisfy a condition if provided, else the count of items.

1 - res = source.count() 2 - res = source.count(lambda x: x > 3)

Keyword arguments: :param types.FunctionType predicate: A function to test each element for a

condition.

Returns:An observable sequence containing a single element with a

number that represents how many elements in the input sequence satisfy the condition in the predicate function if provided, else the count of items in the sequence. :rtype: Observable