24 lines
740 B
Python
24 lines
740 B
Python
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"""
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Line Chart with Cumulative Sum
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This chart creates a simple line chart from the cumulative sum of a fields.
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"""
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# category: line charts
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import altair as alt
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from vega_datasets import data
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source = data.wheat()
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alt.Chart(source).mark_line().transform_window(
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# Sort the data chronologically
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sort=[{'field': 'year'}],
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# Include all previous records before the current record and none after
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# (This is the default value so you could skip it and it would still work.)
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frame=[None, 0],
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# What to add up as you go
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cumulative_wheat='sum(wheat)'
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).encode(
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x='year:O',
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# Plot the calculated field created by the transformation
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y='cumulative_wheat:Q'
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).properties(width=600)
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