widget - 如何使用 IPython Widgets 让一个参数的可能值依赖于另一个参数？

Question

假设我在 Python 中有这个简单的函数:

def f(gender, name):
    if gender == 'male':
        return ranking_male(name)
    else:
        return ranking_female(name)

其中 gender 属于 ['male', 'female'] 而 name 属于 ['Adam', ' John', 'Max', 'Frodo'](如果 gender 为 male)或 ['Mary', 'Sarah', 'Arwen '](否则)。

我希望将 ipywidgets 中的 interact 应用于此函数 f。通常情况下就可以了

from ipywidgets import interact
interact(f, gender = ('male', 'female'), name = ('Adam', 'John', 'Max', 'Frodo'))

问题在于，name 的允许值现在取决于为 gender 选择的值。

我试图在文档中找到它，但找不到。我认为唯一可能重要的是这用于设置特征变化的动态通知。

    Parameters
    ----------
    handler : callable
        A callable that is called when a trait changes. Its
        signature should be ``handler(change)``, where ``change```is a
        dictionary. The change dictionary at least holds a 'type' key.
        * ``type``: the type of notification.
        Other keys may be passed depending on the value of 'type'. In the
        case where type is 'change', we also have the following keys:
        * ``owner`` : the HasTraits instance
        * ``old`` : the old value of the modified trait attribute
        * ``new`` : the new value of the modified trait attribute
        * ``name`` : the name of the modified trait attribute.
    names : list, str, All
        If names is All, the handler will apply to all traits.  If a list
        of str, handler will apply to all names in the list.  If a
        str, the handler will apply just to that name.
    type : str, All (default: 'change')
        The type of notification to filter by. If equal to All, then all
        notifications are passed to the observe handler.

但我不知道该怎么做，也不知道如何解释文档字符串正在谈论的内容。非常感谢任何帮助!

Answer 1

例如，您有汽车的品牌和型号，而型号取决于品牌。

d = {'Volkswagen' : ['Tiguan', 'Passat', 'Polo', 'Touareg', 'Jetta'], 'Chevrolet' : ['TAHOE', 'CAMARO'] }

brand_widget = Dropdown( options=list(d.keys()),
                         value='Volkswagen',
                         description='Brand:',
                         style=style
                       )
model_widget = Dropdown( options=d['Volkswagen'],
                         value=None,
                         description='Model:',
                         style=style
                       )

def on_update_brand_widget(*args):
    model_widget.options = d[brand_widget.value]

brand_widget.observe(on_update_brand_widget, 'value')