Plotly choropleth地图按钮更新color_discrete_map及布局调整问题

问题1：交互更新后颜色异常修复 #

故障原因 #

代码同时配置了互斥的color_continuous_scale（连续色阶）和color_discrete_map（离散颜色映射）参数，布尔类型的疫苗列被Plotly默认识别为数值型，优先调用连续色阶，导致设置的蓝/白离散映射完全失效。

修复步骤 #

• 移除color_continuous_scale="spectral_r"参数，避免参数冲突
• 新增color_discrete_sequence=None参数，强制Plotly触发离散颜色映射逻辑
• 可选：提前将数据中疫苗布尔列转为字符串类型，彻底避免类型识别偏差

问题2：下拉按钮顶部居中调整 #

在updatemenus配置项中新增x=0.5、xanchor="center"两个属性即可，x=0.5对应画布水平中点，xanchor设置按钮的锚点为中心，保证精准居中。可额外调整y参数控制按钮垂直位置，避免和标题重叠。

修正后完整代码 #

import plotly.express as px
import plotly.graph_objects as go

cols_dd = ["Johnson&Johnson","Sinopharm","Sputnik V","Moderna","AstraZeneca","Pfizer","Sinovac","Covaxin"]

fig = go.Figure()

for value in cols_dd:
    fig.add_traces(
        px.choropleth(
            df,
            locations="Iso code",  # Spatial coordinates
            color=value,  # Data to be color-coded
            hover_data={'Iso code':False},
            # 移除冲突的连续色阶参数
            # color_continuous_scale="spectral_r",
            color_discrete_sequence=None, # 新增参数强制启用离散映射
            hover_name="Location",
            color_discrete_map={True: 'blue', False: 'white'})
        .update_traces(visible= True if value==cols_dd[0] else False)
        .data
    )

fig.update_geos(scope="africa")
fig.update_layout(showlegend=True, font=dict(size=12), width = 800, height = 650, margin=dict(l=0,r=0,b=0,t=70),
    title= "<b>Vaccination Brands and Statistics Across Africa</b>",
    updatemenus=[
        {
            "x": 0.5, # 水平位置设为中点
            "xanchor": "center", # 锚点设为按钮中心
            "y": 1.1, # 可调整垂直位置避免和标题重叠
            "buttons": [
                {
                    "label": value,
                    "method": "update",
                    "args": [
                        {"visible": [v2 == value for v2 in cols_dd]},
                        #{"title": f"<b>{value}</b>"},
                    ],
                }
                for value in cols_dd
            ]
        }
    ]
)

fig.show()

内容的提问来源于stack exchange，提问作者Rich