Source code for panel.interact

Interact with functions using widgets.

The interact Pane implemented in this module mirrors
ipywidgets.interact in its API and implementation. Large parts of the
code were copied directly from ipywidgets:

Copyright (c) Jupyter Development Team and PyViz Development Team.
Distributed under the terms of the Modified BSD License.
from __future__ import annotations

import types

from collections import OrderedDict
from import Iterable, Mapping
from inspect import (
    Parameter, getcallargs, getfullargspec as check_argspec, signature,
from typing import TYPE_CHECKING, ClassVar

import param

from .layout import Column, Panel, Row
from .pane import HTML, PaneBase, panel
from .pane.base import ReplacementPane
from .viewable import Viewable
from .widgets import Button, Widget
from .widgets.widget import fixed, widget

    from bokeh.model import Model

empty = Parameter.empty

def _yield_abbreviations_for_parameter(parameter, kwargs):
    """Get an abbreviation for a function parameter."""
    name =
    kind = parameter.kind
    ann = parameter.annotation
    default = parameter.default
    not_found = (name, empty, empty)
    if kind in (Parameter.POSITIONAL_OR_KEYWORD, Parameter.KEYWORD_ONLY):
        if name in kwargs:
            value = kwargs.pop(name)
        elif ann is not empty:
            param.main.param.warning("Using function annotations to implicitly specify interactive controls is deprecated. "
                               "Use an explicit keyword argument for the parameter instead.", DeprecationWarning)
            value = ann
        elif default is not empty:
            value = default
            if isinstance(value, (Iterable, Mapping)):
                value = fixed(value)
            yield not_found
        yield (name, value, default)
    elif kind == Parameter.VAR_KEYWORD:
        # In this case name=kwargs and we yield the items in kwargs with their keys.
        for k, v in kwargs.copy().items():
            yield k, v, empty

[docs]class interactive(PaneBase): default_layout = param.ClassSelector(default=Column, class_=(Panel), is_instance=False) manual_update = param.Boolean(default=False, doc=""" Whether to update manually by clicking on button.""") manual_name = param.String(default='Run Interact') _pane = param.ClassSelector(class_=Viewable) _rename: ClassVar[Mapping[str, str | None]] = {'_pane': None} def __init__(self, object, params={}, **kwargs): if signature is None: raise ImportError('interact requires either recent Python version ' '(>=3.3 or IPython to inspect function signatures.') super().__init__(object, **params) self.throttled = kwargs.pop('throttled', False) new_kwargs = self.find_abbreviations(kwargs) # Before we proceed, let's make sure that the user has passed a set of args+kwargs # that will lead to a valid call of the function. This protects against unspecified # and doubly-specified arguments. try: check_argspec(object) except TypeError: # if we can't inspect, we can't validate pass else: getcallargs(object, **{n:v for n,v,_ in new_kwargs}) widgets = self.widgets_from_abbreviations(new_kwargs) if self.manual_update: widgets.append(('manual', Button(name=self.manual_name))) self._widgets = OrderedDict(widgets) pane = self.object(**self.kwargs) if isinstance(pane, Viewable): self._pane = pane self._internal = False else: self._pane = panel(pane, self._internal = True self._inner_layout = Row(self._pane) widgets = [widget for _, widget in widgets if isinstance(widget, Widget)] if 'name' in params: widgets.insert(0, HTML('<h2>%s</h2>' % self.widget_box = Column(*widgets) self.layout.objects = [self.widget_box, self._inner_layout] self._link_widgets() self._sync_layout() #---------------------------------------------------------------- # Model API #---------------------------------------------------------------- def _get_model(self, doc, root=None, parent=None, comm=None): return self._inner_layout._get_model(doc, root, parent, comm) @param.depends('_pane', '_pane.sizing_mode', '_pane.width_policy', '_pane.height_policy', watch=True) def _sync_layout(self): if not hasattr(self, '_inner_layout'): return opts = { k: v for k, v in self._pane.param.values().items() if k in ('sizing_mode', 'width_policy', 'height_policy') } self._inner_layout.param.update(opts) self.layout.param.update(opts) #---------------------------------------------------------------- # Callback API #---------------------------------------------------------------- @property def _synced_params(self): return [] def _link_widgets(self): if self.manual_update: widgets = [('manual', self._widgets['manual'])] else: widgets = self._widgets.items() for name, widget_obj in widgets: def update_pane(change): # Try updating existing pane new_object = self.object(**self.kwargs) new_pane, internal = ReplacementPane._update_from_object( new_object, self._pane, self._internal ) if new_pane is None: return # Replace pane entirely self._pane = new_pane self._inner_layout[0] = new_pane self._internal = internal if self.throttled and hasattr(widget_obj, 'value_throttled'): v = 'value_throttled' else: v = 'value' pname = 'clicks' if name == 'manual' else v watcher =, pname) self._internal_callbacks.append(watcher) def _cleanup(self, root: Model | None = None) -> None: self._inner_layout._cleanup(root) super()._cleanup(root) #---------------------------------------------------------------- # Public API #---------------------------------------------------------------- @property def kwargs(self): return {k: widget.value for k, widget in self._widgets.items() if k != 'manual'} def signature(self): return signature(self.object)
[docs] def find_abbreviations(self, kwargs): """Find the abbreviations for the given function and kwargs. Return (name, abbrev, default) tuples. """ new_kwargs = [] try: sig = self.signature() except (ValueError, TypeError): # can't inspect, no info from function; only use kwargs return [ (key, value, value) for key, value in kwargs.items() ] for parameter in sig.parameters.values(): for name, value, default in _yield_abbreviations_for_parameter(parameter, kwargs): if value is empty: raise ValueError('cannot find widget or abbreviation for argument: {!r}'.format(name)) new_kwargs.append((name, value, default)) return new_kwargs
[docs] def widgets_from_abbreviations(self, seq): """Given a sequence of (name, abbrev, default) tuples, return a sequence of Widgets.""" result = [] for name, abbrev, default in seq: if isinstance(abbrev, fixed): widget_obj = abbrev else: widget_obj = widget(abbrev, name=name, default=default) if not (isinstance(widget_obj, Widget) or isinstance(widget_obj, fixed)): if widget_obj is None: continue else: raise TypeError("{!r} is not a ValueWidget".format(widget)) result.append((name, widget_obj)) return result
[docs] @classmethod def applies(cls, object): return isinstance(object, types.FunctionType)
# Return a factory for interactive functions @classmethod def factory(cls): options = dict(manual_update=False, manual_name="Run Interact") return _InteractFactory(cls, options)
class _InteractFactory(object): """ Factory for instances of :class:`interactive`. Arguments --------- cls: class The subclass of :class:`interactive` to construct. options: dict A dict of options used to construct the interactive function. By default, this is returned by ``cls.default_options()``. kwargs: dict A dict of **kwargs to use for widgets. """ def __init__(self, cls, options, kwargs=None): self.cls = cls self.opts = options self.kwargs = kwargs or {} def widget(self, f): """ Return an interactive function widget for the given function. The widget is only constructed, not displayed nor attached to the function. Returns ------- An instance of ``self.cls`` (typically :class:`interactive`). Parameters ---------- f : function The function to which the interactive widgets are tied. """ return self.cls(f, self.opts, **self.kwargs) def __call__(self, __interact_f=None, **kwargs): """ Make the given function interactive by adding and displaying the corresponding :class:`interactive` widget. Expects the first argument to be a function. Parameters to this function are widget abbreviations passed in as keyword arguments (``**kwargs``). Can be used as a decorator (see examples). Returns ------- f : __interact_f with interactive widget attached to it. Parameters ---------- __interact_f : function The function to which the interactive widgets are tied. The `**kwargs` should match the function signature. Passed to :func:`interactive()` **kwargs : various, optional An interactive widget is created for each keyword argument that is a valid widget abbreviation. Passed to :func:`interactive()` Examples -------- Render an interactive text field that shows the greeting with the passed in text:: # 1. Using interact as a function def greeting(text="World"): print("Hello {}".format(text)) interact(greeting, text="IPython Widgets") # 2. Using interact as a decorator @interact def greeting(text="World"): print("Hello {}".format(text)) # 3. Using interact as a decorator with named parameters @interact(text="IPython Widgets") def greeting(text="World"): print("Hello {}".format(text)) Render an interactive slider widget and prints square of number:: # 1. Using interact as a function def square(num=1): print("{} squared is {}".format(num, num*num)) interact(square, num=5) # 2. Using interact as a decorator @interact def square(num=2): print("{} squared is {}".format(num, num*num)) # 3. Using interact as a decorator with named parameters @interact(num=5) def square(num=2): print("{} squared is {}".format(num, num*num)) """ # If kwargs are given, replace self by a new # _InteractFactory with the updated kwargs if kwargs: params = list(interactive.param) kw = dict(self.kwargs) kw.update({k: v for k, v in kwargs.items() if k not in params}) opts = dict(self.opts, **{k: v for k, v in kwargs.items() if k in params}) self = type(self)(self.cls, opts, kw) f = __interact_f if f is None: # This branch handles the case 3 # @interact(a=30, b=40) # def f(*args, **kwargs): # ... # # Simply return the new factory return self elif 'throttled' in check_argspec(f).args: raise ValueError('A function cannot have "throttled" as an argument') # positional arg support in: # Handle the cases 1 and 2 # 1. interact(f, **kwargs) # 2. @interact # def f(*args, **kwargs): # ... w = self.widget(f) try: f.widget = w except AttributeError: # some things (instancemethods) can't have attributes attached, # so wrap in a lambda f = lambda *args, **kwargs: __interact_f(*args, **kwargs) f.widget = w return w.layout def options(self, **kwds): """ Change options for interactive functions. Returns ------- A new :class:`_InteractFactory` which will apply the options when called. """ opts = dict(self.opts) for k in kwds: if k not in opts: raise ValueError("invalid option {!r}".format(k)) opts[k] = kwds[k] return type(self)(self.cls, opts, self.kwargs) interact = interactive.factory() interact_manual = interact.options(manual_update=True, manual_name="Run Interact") __all__ = ["interact", "interact_manual", "interactive"]