live data Dash plot with python - python-3.x

Question

i have write a code in python to plot data in realtime. there is only one problem the code run i get no errors but there is also no plot in web page that i created.
can any one help me pleadse?
thanks
ma code
#app work
app = dash.Dash(__name__)
#html layout
app.layout = html.Div(
[
dcc.Graph(id = 'live-graph',
animate = True),
dcc.Interval(
id = 'graph-update',
interval = 1*1000,
n_intervals = 0 ),])

Answer 1

I recommend checking the data in raw[0] and raw1 and I do not think you need list(str()). You need also to bring the data from the database by increasing the value after LIMIT. Therefore, you should let the size of the data coming from the database increase dynamically and being controlled by n_intervals such that select * from ..... LIMIT + n and absolutely the value of n should start from 1, therefore set n_intervals to 1 accordingly. Another error in your program, you return figure which is not graph_object and dbc.Graph expects graph_object.
In the example below, I created a dataframe from CSV file, but you can understand the logic and apply it directly to your example:
from dash import Dash, html, dcc
import plotly.graph_objects as go
from dash.dependencies import Input, Output
import pandas as pd
import numpy
app = Dash(__name__)
df = pd.read_csv("data.csv")
app.layout = html.Div(
[
dcc.Graph(id='live-graph'),
dcc.Interval(
id='interval-component',
interval=1000, # in milliseconds
n_intervals = 1, # start
),
]
)
#app.callback(
Output('live-graph', 'figure'),
[Input('interval-component', 'n_intervals')]
)
def update_graph_scatter(n):
if n <= len(df):
row = df.iloc[:n,:]
w = numpy.asarray(row[df.columns[0]])
volt = numpy.asarray(row[df.columns[1]])
data = go.Scatter( x = w , y = volt , hoverinfo='text+name+y', name='Scatter', mode= 'lines+markers', )
layout = go.Layout(xaxis = dict(range=[min(w),max(w)]), yaxis = dict(range=[min(volt)-1,max(volt)+1]))
figure = go.Figure({'data' :data, 'layout' : layout})
return figure
app.run_server(debug=True, use_reloader=False)