如何使用 Plotly Python 对事件的直方图进行动画处理？

Question

I want to animate a histogram over a DataFrame index, so that as the index increases, the bins fill up. My DataFrame is structured like this:

Index	Ingredient
1	Onions
2	Onions
3	Garlic
4	Onions
5	Tomato
6	Tomato
7	Onions

At the beginning of the animation, all bins should be initialized at 0, and fill up as the index increases. I have tried the following using plotly.express.histogram .

idx = df.index
fig = px.histogram(df, x="Ingredient",
    animation_frame=idx, animation_group=idx, cumulative=True,
)

The result I get is an animated histogram with only one bin that switches between the ingredient names as it goes through the DataFrame , with the height of the bin staying constant at 1.

Answer 1

• approach is to prepare a dataframe that is ready for animation
• then it's simple to create an animated bar to create figure you have defined

import pandas as pd
import plotly.express as px
import io

df = pd.read_csv(
    io.StringIO(
        """Index,Ingredient
1,Onions
2,Onions
3,Garlic
4,Onions
5,Tomato
6,Tomato
7,Onions"""
    )
)


ings = df["Ingredient"].value_counts()
df2 = pd.concat(
    [
        pd.DataFrame({"Ingredient": ings.index})
        .merge(
            df.loc[df["Index"].le(i)].groupby("Ingredient", as_index=False).size(),
            on="Ingredient",
            how="left",
        )
        .assign(Index=i)
        .fillna(0)
        for i in range(df["Index"].min(), df["Index"].max() + 1)
    ]
)

px.bar(df2, x="Ingredient", y="size", animation_frame="Index").update_layout(
    yaxis={"range": [0, ings.max()]}
)