问在IPython小部件中动态添加和删除列表项
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Stack Overflow用户

提问于 2020-11-19 13:37:20

回答 1查看 391关注 0票数 1

我正在尝试使用ipywidgets在Ipython Jupyter Notebook中实现一个基本的待办事项列表应用。

我可以很容易地实现将项目添加到我的列表中的功能，但是，如果单击“删除”按钮，我无法正确处理现有项目的删除。整个代码在单个单元中运行。

import ipywidgets as widgets
from ipywidgets import VBox, HBox, Text, Button
from IPython.display import display

todo = []

def completed_sentence(sentence): 
    """ To display existing notes with a 'Remove' button """
    sentenceField = Text(value=sentence)
    removeButton = Button(description='Remove',
                          button_style='danger')
    return HBox([sentenceField, removeButton])

def render_sentences(_):
    """ To update the view """
    global a,b
    if a.value != '':
        todo.append(a.value)
    a.value = ''
        todoWidget.children = tuple\
            ([VBox([VBox([completed_sentence(each) 
                          for each in todo]),
                    HBox([a, b])])])
    
# Setting up a basic view- with an empty field and a button
a = widgets.Text(value='')
b = widgets.Button(description='Add')                                 
b.on_click(render_sentences)

todoWidget = widgets.HBox([a, b])
display(todoWidget)

现在，为了能够删除句子，我将函数completed_sentence的定义更新如下：

def completed_sentence(sentence):
    """ To display existing notes """
    def remove_sentence(_):
        global render_sentences
        try:
            if todo.index(sentenceField.value) >= 0:
                todo.remove(sentenceField.value)
                render_sentences()
        except:
            return 
                
    sentenceField = Text(value=sentence)
    removeButton = Button(description='Remove', button_style='danger')
    removeButton.on_click(remove_sentence)
    return HBox([sentenceField, removeButton])

但是现在，这有一个问题，它对render_sentences的调用被忽略了！如果您愿意，使用Ipython小部件来处理这种“反应式”编程的最佳方式是什么？

python

jupyter-notebook

ipywidgets

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回答 1

Stack Overflow用户

发布于 2020-11-19 13:52:00

更新completed_sentence的定义似乎可以完成这项工作。但它仍然是一个谜，为什么原始的定义不起作用。

def completed_sentence(sentence):
    def remove_sentence(_):
        global render_sentences
        try:
            if todo.index(sentenceField.value) >= 0:
                todo.remove(sentenceField.value)
        except:
            pass
        render_sentences(_)
                
    sentenceField = Text(value=sentence)
    removeButton = Button(description='Remove', button_style='danger')
    removeButton.on_click(remove_sentence)
    sentence_view = HBox([sentenceField, removeButton])
    return sentence_view