带有累计求和的折线图

此图表通过对字段进行累计求和来创建简单的折线图。

方法语法

import altair as alt
from vega_datasets import data

source = data.wheat()

alt.Chart(source, width=600).mark_line().transform_window(
    # Sort the data chronologically
    sort=[{'field': 'year'}],
    # Include all previous records before the current record and none after
    # (This is the default value so you could skip it and it would still work.)
    frame=[None, 0],
    # What to add up as you go
    cumulative_wheat='sum(wheat)'
).encode(
    x='year:O',
    # Plot the calculated field created by the transformation
    y='cumulative_wheat:Q'
)

属性语法

import altair as alt
from vega_datasets import data

source = data.wheat()

alt.Chart(source).mark_line().transform_window(
    # Sort the data chronologically
    sort=[{'field': 'year'}],
    # Include all previous records before the current record and none after
    # (This is the default value so you could skip it and it would still work.)
    frame=[None, 0],
    # What to add up as you go
    cumulative_wheat='sum(wheat)'
).encode(
    x='year:O',
    # Plot the calculated field created by the transformation
    y='cumulative_wheat:Q'
).properties(width=600)