param.reactive.reactive_ops.len

reactive_ops.len() → rx

Return the length of the current object as a reactive expression.

Since the __len__ method cannot be overloaded reactively, this method provides a way to compute the length of the current reactive expression. The result is returned as a new reactive expression.

Returns:

A new reactive expression representing the length of the object.

Return type:

rx

Examples

Compute the length of a reactive list:

>>> import param
>>> rx_list = param.rx([1, 2, 3])
>>> rx_len = rx_list.rx.len()
>>> rx_len.rx.value
3

Update the reactive list and observe the length update:

>>> rx_list.rx.value = [1, 2, 3, 4, 5]
>>> rx_len.rx.value
5

Compute the length of a reactive string:

>>> rx_string = param.rx("Hello World")
>>> rx_len = rx_string.rx.len()
>>> rx_len.rx.value
11