Question

我目前正在创建一个从pandas继承DataFrame的Class。我有兴趣开发一种名为＆＃39; new_filter＆＃39;这是一个更精彩的DataFrame命令执行：

$ xmllint --schematron sample-schematron.schema.xml sample-schematron.xml
sample-schematron.schema.xml:11: element rule: Schemas parser error : Failed to compile context expression Person[@Title='Mr']
Schematron schema sample-schematron.schema.xml failed to compile

$ xmllint --version
xmllint: using libxml version 20706
   compiled with: Threads Tree Output Push Reader Patterns Writer SAXv1 FTP HTTP DTDValid HTML Legacy C14N Catalog XPath XPointer XInclude Iconv ISO8859X Unicode Regexps Automata Expr Schemas Schematron Modules Debug Zlib

创建像：

之类的对象

import pandas as pd
from ipywidgets import widgets
from IPython.display import display
import numpy as np

class Result(pd.DataFrame):

@property
def _constructor(self):
    return Result

def _filter_done(self, c):
    self._column_name = self._filter_dd.value
    self._expression = self._filter_txt.value
    return self[eval('self.'+ self._column_name +'  '+self._expression)]

def new_filter(self):
    self._filter_dd = widgets.Dropdown(options=list(self.columns),
                                            description='Column:')
    self._filter_txt = widgets.Text(description='Expr:')
    self._filter_button = widgets.Button(description = 'Done')
    self._filter_box = widgets.VBox([self._filter_dd, self._filter_txt, self._filter_button])
    display(self._filter_box)
    self._filter_button.on_click(self._filter_done)

然后，例如： Widget Output

我想要的是＆＃39; test_2＆＃39;成为＆＃39;结果＆＃39;的对象类。这有什么解决方案吗？

Answer 1

首先，您必须在函数new_filter中返回一些内容。其次，如果你想要修改同一个对象，我认为这有点难。你可以做的一件事就是让一个具有特征的对象可以在_filter_done中更新。

以下是一个如何做到这一点的小例子：

import pandas as pd
from ipywidgets import widgets
from IPython.display import display
import numpy as np

class Result(pd.DataFrame):
    @property
    def _constructor(self):
        return Result

    def _filter_done(self, obj, c):
        ## obj is the obejct to be modified. 
        ## Updating its data attribute to have the filtered data.
        self._column_name = self._filter_dd.value
        self._expression = self._filter_txt.value
        obj.data = self[eval('self.'+ self._column_name +'  '+self._expression)]

    def new_filter(self):
        self._filter_dd = widgets.Dropdown(options=list(self.columns),
                                            description='Column:')
        self._filter_txt = widgets.Text(description='Expr:')
        self._filter_button = widgets.Button(description = 'Done')
        self._filter_box = widgets.VBox([self._filter_dd, self._filter_txt, self._filter_button])
        display(self._filter_box)

        result_obj = FilterResult()
        self._filter_button.on_click(lambda arg: self._filter_done(result_obj, arg))
        return result_obj

from traitlets import HasTraits
from traittypes import DataFrame

class FilterResult(HasTraits):
    data = DataFrame()

使用与您的问题相同的示例代码，即

test = Result(np.random.randn(3,4), columns=['A', 'B', 'C','D']) #just an example
test_2 = test.new_filter()

您可以看到，点击“完成”后，更新的dataframe位于test_2.data。

使用ipywidgets按钮返回DataFrame

1 个答案: