I have a question about doing functions in dash using python.
Here is the code I'm studying:
import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output
external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']
app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
app.layout = html.Div([
html.H6("Change the value in the text box to see callbacks in action!"),
html.Div(["Input: ",
dcc.Input(id='my-input', value='initial value', type='text')]),
html.Br(),
html.Div(id='my-output'),
])
@app.callback(
Output(component_id='my-output', component_property='children'),
Input(component_id='my-input', component_property='value')
)
def update_output_div(input_value):
return 'Output: {}'.format(input_value)
if __name__ == '__main__':
app.run_server(debug=True)
After the callback, we have a function "update_output_div", and a parameter named "input_value", but how the code knows that the input_value is the component_property of the component_id named "my-input? The first answer for this question was because of the order, but and in this case:
@app.callback(
[Output(component_id='plot1', component_property='children'),
Output(component_id='plot2', component_property='children'),
Output(component_id='plot3', component_property='children'),
Output(component_id='plot4', component_property='children'),
Output(component_id='plot5', component_property='children')],
[Input(component_id='input-type', component_property='value'),
Input(component_id='input-year', component_property='value')],
# REVIEW4: Holding output state till user enters all the form information. In this case, it will be chart type and year
[State("plot1", 'children'), State("plot2", "children"),
State("plot3", "children"), State("plot4", "children"),
State("plot5", "children")])
# Add computation to callback function and return graph
def get_graph(chart, year, children1, children2, c3, c4, c5):
?
It respects an order :
The first Input component_property will be taken as the first argument of your function, for example :
@app.callback(
Output(component_id='my-output', component_property='children'),
Input(component_id='my-input1', component_property='value1'),
Input(component_id='my-input2', component_property='value2'),
Input(component_id='my-input3', component_property='value3'),
State(component_id='my-input4', component_property='value4'),
State(component_id='my-input5', component_property='value5')
)
def update_output_div(value1, value2, value3, value4, value5):
return func(value1, value2, value3, value4, value5)
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