param.reactive.reactive_ops.map#

reactive_ops.map(func, /, *args, **kwargs) → rx[source]#

Apply a function to each item in the reactive collection.

This method applies a given function to every item in the current reactive collection and returns a new reactive expression containing the results.

Parameters:

  • func (callable) – The function to apply to each item in the collection.

  • *args (iterable, optional) – Positional arguments to pass to the function.

  • **kwargs (dict, optional) – Keyword arguments to pass to the function.

Returns:

A new reactive expression containing the results of applying func to each item.

Return type:

rx

Raises:

TypeError – If func is a generator or asynchronous generator function, which are not supported.

Examples

Apply a function to double each item in a reactive list:

>>> import param
>>> reactive_list = param.rx([1, 2, 3])
>>> reactive_doubled = reactive_list.rx.map(lambda x: x * 2)
>>> reactive_doubled.rx.value
[2, 4, 6]

Use positional arguments in the function:

>>> reactive_offset = reactive_list.rx.map(lambda x, offset: x + offset, offset=10)
>>> reactive_offset.rx.value
[11, 12, 13]

Use keyword arguments in the function:

>>> reactive_power = reactive_list.rx.map(lambda x, power=1: x ** power, power=3)
>>> reactive_power.rx.value
[1, 8, 27]