[英]Is it possible to dynamically load dcc.Dropdown option from values in Plotly Dash, dcc.store?
The application is built to store values from dcc.Input
and display it on a dash_table
.该应用程序旨在存储来自
dcc.Input
的值并将其显示在dash_table
上。 For the purpose of storing the input values dcc.store
is being used.为了存储输入值,使用了
dcc.store
。
Now I need to dynamically load the values of the first column ie "Student Name" in the dcc.Dropdown
as options.现在我需要动态加载第一列的值,即
dcc.Dropdown
中的“学生姓名”作为选项。 Is there a possible way to share the data of the first column in dcc.store
as an input to the options in dcc.Dropdown
?是否有可能共享 dcc.store 中第一列的数据作为
dcc.store
中选项的dcc.Dropdown
?
import dash
import dash_core_components as dcc
import dash_html_components as html
import dash_table
from dash.dependencies import Output, Input, State
user_key = 'Student Name'
# Setup table.
columns = ['Student Name',
'Age',
'Place',
'Grade']
table = dash_table.DataTable(columns=[{"name": column, "id": column} for column in columns],
data=[], id="table")
# Create app.
app = dash.Dash(prevent_initial_callbacks=True)
app.layout = html.Div([
html.Div([dcc.Input(id=column, value=column) for column in columns] +
[html.Button("Save", id="save"), dcc.Store(id="cache", data=[]), table]),
html.Div([
dcc.Dropdown(
id='demo-dropdown',
options=[
{'label': 'Mark', 'value': 'mrc'},
],
value='mrc'
)
])
])
@app.callback(Output("table", "data"),
[Input("save", "n_clicks")],
[State("table", "data")] +
[State(column, "value") for column in columns])
def update_table(n_clicks, data, *args):
record = {columns[i]: arg for i, arg in enumerate(list(args))}
try:
record_index = [record[user_key] for record in data].index(record[user_key])
data[record_index] = record
except ValueError:
data.append({columns[i]: arg for i, arg in enumerate(list(args))})
return data
if __name__ == '__main__':
app.run_server()
Yes you can load from dcc.Store()
that has been populated with some dataframe. You will need a callback which takes in the Store's modified_timestamp property as the Input() and its data as a State() explained in Dash's official documentation ).是的,您可以从已填充一些 dataframe 的
dcc.Store()
加载。您将需要一个回调,它将 Store 的 modified_timestamp 属性作为 Input() 并将其数据作为 State(),在Dash 的官方文档中进行了解释)。 So something like this callback will do the trick:所以像这样的回调就可以解决问题:
@app.callback(
[Output("demo-dropdown", "options"), Output("demo-dropdown", "value")],
[Input("cache", "modified_timestamp")],
State("cache", "data"),
)
def update_dropdown_from_store(time_stamp, data):
return (
[
[{"label": i, "value": i} for i in list(df["Student Name"])],
df["Student Name"].iloc[0],
]
if data != []
else [[{"label": "Mark", "value": "mrc"}], "mrc"]
)
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