Dash开发报错：'Dash' object has no attribute 'html' 求助

你遇到的错误根源是代码里错误地通过app.html.Div调用HTML组件——实际上你已经通过import dash_html_components as html导入了html组件，直接使用html.Div即可，无需通过app对象调用。

修正后的完整代码 #

import dash
from dash.dependencies import Input, Output
import dash_html_components as html
import dash_core_components as dcc
import pandas as pd

app = dash.Dash()

app.layout = html.Div([  # 移除app.html前缀，直接使用html.Div
    html.H1('Training Data Set'),
    dcc.Upload(id='upload-training-data', children=html.Div([
        'Drag and Drop or ',
        html.A('Select Files')
    ])),
    html.H1('Meta Data'),
    dcc.Upload(id='upload-meta-data', children=html.Div([
        'Drag and Drop or ',
        html.A('Select Files')
    ])),
    html.H1('Validation Data Set'),
    dcc.Upload(id='upload-validation-data', children=html.Div([
        'Drag and Drop or ',
        html.A('Select Files')
    ]))
])

# 必须添加这段代码才能启动Dash服务器
if __name__ == '__main__':
    app.run_server(debug=True)

额外优化提示 #

Dash 2.x及以上版本推荐更简洁的组件导入方式，替代旧版的dash_html_components和dash_core_components，可以改成如下写法：

from dash import Dash, html, dcc, Input, Output
import pandas as pd

app = Dash()

app.layout = html.Div([
    html.H1('Training Data Set'),
    dcc.Upload(id='upload-training-data', children=html.Div([
        'Drag and Drop or ',
        html.A('Select Files')
    ])),
    html.H1('Meta Data'),
    dcc.Upload(id='upload-meta-data', children=html.Div([
        'Drag and Drop or ',
        html.A('Select Files')
    ])),
    html.H1('Validation Data Set'),
    dcc.Upload(id='upload-validation-data', children=html.Div([
        'Drag and Drop or ',
        html.A('Select Files')
    ]))
])

if __name__ == '__main__':
    app.run_server(debug=True)

内容的提问来源于stack exchange，提问作者Vijaya Kumar