Python 单击dash中的按钮后,从数据框填充dash_表
我已经开始仔细观察dash/了,不知道我做错了什么。我想通过回调用dash_表更新div。数据来自dataframe/db查询 我试图把代码删减到最低限度Python 单击dash中的按钮后,从数据框填充dash_表,python,plotly,plotly-dash,Python,Plotly,Plotly Dash,我已经开始仔细观察dash/了,不知道我做错了什么。我想通过回调用dash_表更新div。数据来自dataframe/db查询 我试图把代码删减到最低限度 import dash import dash_table import dash_core_components as dcc import dash_html_components as html import dash_bootstrap_components as dbc from dash.dependencies import O
import dash
import dash_table
import dash_core_components as dcc
import dash_html_components as html
import dash_bootstrap_components as dbc
from dash.dependencies import Output, Input, State
import datetime
import re
import pandas as pd
import plotly.graph_objects as go
app = dash.Dash()
app.layout = html.Div(children=[html.Div("Dashboard",
style={"color": "white", "text-align": "center", "background-color": "blue", "display": "inline-block", "width": "100%", "font-size": "46px",
}),
dcc.Tabs([
dcc.Tab(label='Upcoming events',
children=[
html.Div("Select a period: ",
style={"text-align": "center"}),
html.Div(
dcc.DatePickerRange(
id="calendar_period",
start_date_placeholder_text="Start Period",
end_date_placeholder_text="End Period",
start_date=datetime.datetime.today(),
end_date=datetime.datetime.today(),),
style={"text-align": "center"}
),
html.Div(
html.Button("Retrieve calendar", id="submit_period", n_clicks=0),
style={"text-align": "center"}
),
html.H1(id='calendar_table'),
]),
dcc.Tab(label='Some other tab',)
])
])
@app.callback(
[Output('calendar_table', 'children')],
[Input('calendar_period', 'start_date'), Input('calendar_period', 'end_date')],
[State('submit_period', 'n_clicks')])
def retrieve_calendar(start_date, end_date, n_clicks):
events = pd.read_sql_query(...) #<- query based on start_date and end_date both in date format
columns = [{"name": i, "id": i, } for i in events.columns]
df_data = events.to_dict('rows')
return dash_table.DataTable(data=df_data, columns=columns)
if __name__ == '__main__':
app.run_server(debug=True)
但也没有出现什么
编辑:我收到以下错误消息:
回调..日历\表.子项。。是一个多输出
有点混乱,因为我的回调只定义了一个输出:
Output('calendar_table', 'children')
我还补充说:
def retrieve_earnings(start_date, end_date, n_clicks):
events = pd...
print(events.head())
columns = [{"name": i, "id": i, } for i in events.columns]
print(columns)
df_data = events.to_dict('records')
print(df_data)
return dash_table.DataTable(data=df_data, columns=columns)
我得到两次
Empty DataFrame
启动编程大约5秒钟后(减去选择日期范围的时间),打印(events.head())将在Python控制台中显示正确的数据,但仍然存在相同的多输出错误,并且127.0.0.1上没有显示数据表
Edit2:我将submit_period按钮的状态切换为Input,并返回[dash_table.DataTable(…)],这似乎完成了“技巧”,但在这种情况下,submit按钮无效…回调将输出定义为长度为1的列表。Dash认为这是一个多输出回调。去掉方括号(
[
,]
),只给它输出()。这将解决您的错误
Empty DataFrame