散景: pandas 数据框的图表不会在触发时更新 [英] Bokeh: chart from pandas dataframe won't update on trigger

问题描述

我有一个pandas数据框，我想使用Bokeh服务器将其列显示为图中的线条.另外，我想有一个滑块来使其中一条线相对另一条线移动.

I have got a pandas dataframe whose columns I want to show as lines in a plot using a Bokeh server. Additionally, I would like to have a slider for shifting one of the lines against the other.

我的问题是滑块值更改时的更新功能.我已经尝试过bokeh的滑块示例中的代码，但是它不起作用.

My problem is the update functionality when the slider value changes. I have tried the code from the sliders-example of bokeh, but it does not work.

这是一个例子

import pandas as pd
from bokeh.io import vform
from bokeh.plotting import Figure, output_file, show
from bokeh.models import CustomJS, ColumnDataSource, Slider

df = pd.DataFrame([[1,2,3],[3,4,5]])
df = df.transpose()
myindex = list(df.index.values)
mysource = ColumnDataSource(df)

plot = Figure(plot_width=400, plot_height=400)

for i in range(len(mysource.column_names) - 1):
    name = mysource.column_names[i]    
    plot.line(x = myindex, y = str(name), source = mysource)

offset = Slider(title="offset", value=0.0, start=-1.0, end=1.0, step=1)

def update_data(attrname, old, new):
    # Get the current slider values
    a = offset.value

    temp = df[1].shift(a)
    #to finish#

offset.on_change('value', update_data)

layout = vform(offset, plot)

show(layout)

在update_data函数内部，我必须更新mysource，但是我不知道该怎么做.有人能指出我正确的方向吗?

Inside the update_data-function I have to update mysource, but I cannot figure out how to do that. Can anybody point me in the right direction?

推荐答案

尝试一下...将a=offset.value更改为a=cb_obj.get('value')

Give this a try... change a=offset.value to a=cb_obj.get('value')

然后在尝试执行的所有操作之后将source.trigger('change')放在该update_data函数而不是offset.on_change('value', update_data)中.

Then put source.trigger('change') after you do whatever it is you are trying to do in that update_data function instead of offset.on_change('value', update_data).

还要更改offset = Slider(title="offset", value=0.0, start=-1.0, end=1.0, step=1, callback=CustomJS.from_py_func(offset))

请注意，我使用的这种格式已安装flexx. https://github.com/zoofio/flexx 如果您使用的是Python 3.5，则必须下载压缩文件，解压缩并键入python setup.py install，因为尚未发布该版本的文件...

Note this format I'm using works with flexx installed. https://github.com/zoofio/flexx if you have Python 3.5 you'll have to download the zip file, extract, and type python setup.py install as it isn't posted yet compiled for this version...

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