我的 HoloViews Python 代碼中的 vdims 有什么問題？

Question

display(df_top5_frac.head())

下面的代碼產生一個錯誤。

%opts Overlay [width=800 height=600 legend_position='top_right'] Curve

hv.Curve((df_top5_frac['Blocked Driveway'])      , kdims = ['Hour'], vdims = ['Fraction'], label = 'Blocked Driveway') *\
hv.Curve((df_top5_frac['HEAT/HOT WATER'])        , kdims = ['Hour'], vdims = ['Fraction'], label = 'HEAT/HOT WATER') *\
hv.Curve((df_top5_frac['Illegal Parking'])       , kdims = ['Hour'], vdims = ['Fraction'], label = 'Illegal Parking') *\
hv.Curve((df_top5_frac['Street Condition'])      , kdims = ['Hour'], vdims = ['Fraction'], label = 'Street Condition') *\
hv.Curve((df_top5_frac['Street Light Condition']), kdims = ['Hour'], vdims = ['Fraction'], label = 'Street Light Condition')

這是錯誤：

Answer 1

你的錯誤原因：
vdim 應該是您希望在 y 軸上具有的列的名稱，但列名稱“分數”不存在，因此您會收到錯誤消息。

這是一個可能的解決方案：
當您將小時設置為索引時，您可以指定： kdim='hour'和vdim='blocked_driveway' ，但在這種情況下，您並不真正需要它們，可以將它們排除在外：

# import libraries
import numpy as np
import pandas as pd
import holoviews as hv
hv.extension('bokeh')

# create sample data
data = {'hour': ['00', '01', '02'],
        'blocked_driveway': np.random.uniform(size=3),
        'illegal_parking': np.random.uniform(size=3),
        'street_condition': np.random.uniform(size=3),}

# create dataframe and set hour as index
df = pd.DataFrame(data).set_index('hour')

# create curves: 
# in this case the index is automatically taken as kdim
# and the series variable, e.g. blocked_driveway is taken as vdim
plot1 = hv.Curve(df['blocked_driveway'], label='blocked_driveway')
plot2 = hv.Curve(df['illegal_parking'], label='illegal_parking')
plot3 = hv.Curve(df['street_condition'], label='street_condition')

# put plots together
(plot1 * plot2 * plot3).opts(legend_position='top', width=600, height=400)

替代和更短的解決方案：
在這種情況下，但是我會用庫hvplot這是建立在holoviews的頂部。
它的語法更簡單，你需要更少的代碼來獲得你想要的圖：

import hvplot.pandas

# you don't have to set hour as index this time, but you could if you'd want to.
df.hvplot.line(
    x='hour', 
    y=['blocked_driveway', 
       'illegal_parking',
       'street_condition'],
)

結果圖：