Shapelets平台使用Altair示例报错：Widget不支持spec参数

问题重现 #

在Shapelets平台运行Altair图表示例时，执行代码触发以下错误：

TypeError: Widget.__init__() got an unexpected keyword argument 'spec'

涉事代码如下：

import altair as alt
import pandas as pd

app = DataApp(name="altair example")

# Define the data source
source = pd.DataFrame({'Horsepower': [130, 165, 150, 150, 140, 198],
                       'Miles_per_Gallon': [27.0, 28.0, 25.0, 25.0, 27.0, 17.0],
                       'Origin': ['USA', 'USA', 'USA', 'USA', 'USA', 'Europe'],
                       'Name': ['mazda rx4', 'mazda rx4 wag', 'datsun 710', 'hornet 4 drive', 'hornet sportabout', 'volvo 142e']})

# Define the Altair chart
spec = alt.Chart(source).mark_circle(size=60).encode(
    x='Horsepower',
    y='Miles_per_Gallon',
    color='Origin',
    tooltip=['Name', 'Origin', 'Horsepower', 'Miles_per_Gallon']
).interactive()

# Create the Altair chart component
altair_chart = app.altair_chart(title='Altair Chart 2', spec=spec)

# Add the chart to the app
app.place(altair_chart)

# Register the app
app.register()

问题原因 #

Shapelets的app.altair_chart()方法不支持spec参数，正确用来传入Altair Chart对象的参数是chart。

解决方案 #

将创建Altair图表组件的代码行中，spec=spec替换为chart=spec即可。

修改后的完整代码 #

import altair as alt
import pandas as pd

app = DataApp(name="altair example")

# Define the data source
source = pd.DataFrame({'Horsepower': [130, 165, 150, 150, 140, 198],
                       'Miles_per_Gallon': [27.0, 28.0, 25.0, 25.0, 27.0, 17.0],
                       'Origin': ['USA', 'USA', 'USA', 'USA', 'USA', 'Europe'],
                       'Name': ['mazda rx4', 'mazda rx4 wag', 'datsun 710', 'hornet 4 drive', 'hornet sportabout', 'volvo 142e']})

# Define the Altair chart
spec = alt.Chart(source).mark_circle(size=60).encode(
    x='Horsepower',
    y='Miles_per_Gallon',
    color='Origin',
    tooltip=['Name', 'Origin', 'Horsepower', 'Miles_per_Gallon']
).interactive()

# 修正参数名：将spec改为chart
altair_chart = app.altair_chart(title='Altair Chart 2', chart=spec)

# Add the chart to the app
app.place(altair_chart)

# Register the app
app.register()

内容的提问来源于stack exchange，提问作者Amelia Patel