Use of slider to vary a timeinterval on which a mean value is calculated

[TONODEKEN]

What is your suggestion?

Can someone help to correct this code which is generated wth copilot : I want to use a slider to change the interval (in seconds) on which he calculates the mean value of the 3th signal between the 2 vertical rulers. The first rule is fixed and the second ruler must vary an the mean value must adapt itself. The value if the slider must be added to the time of the first vertical ruler.
I have generated different variants of this code but none of them works

import pandas as pd
import numpy as np
import altair as alt

Sample data

data = {
'timestamp': pd.date_range(start='2023-01-01 00:00:00', periods=100, freq='s'),
'signal1': np.random.randn(100).cumsum(),
'signal2': np.random.randn(100).cumsum(),
'signal3': np.random.randn(100).cumsum()
}

df = pd.DataFrame(data)

Find the index where the difference between signal1 and signal2 is minimal

min_diff_index = (df['signal1'] - df['signal2']).abs().idxmin()
print(min_diff_index)

Create a slider for the interval

slider = alt.binding_range(min=1, max=20, step=1, name='Interv')
interval = alt.param(value=10, bind=slider)

Calculate the mean value of signal3 between the min_diff_index and the next interval seconds

def calculate_mean_signal3(df, min_diff_index, interval):
print(min_diff_index, interval, len(df))
end_index = min((min_diff_index + interval), len(df))
end_index = min_diff_index + 10
print('end_index :', end_index)
return df['signal3'][min_diff_index:end_index].mean()

mean_signal3 = calculate_mean_signal3(df, min_diff_index, interval.value)
print('mean :', mean_signal3)

Create the Altair chart with formatted tooltip

base = alt.Chart(df).encode(
x=alt.X('timestamp:T', title='Time')
)

line1 = base.mark_line(color='blue').encode(
y=alt.Y('signal1:Q', title='Signal 1'),
tooltip=[alt.Tooltip('timestamp:T', title='Time', format='%Y-%m-%d %H:%M:%S'), alt.Tooltip('signal1:Q', title='Signal 1')]
)

line2 = base.mark_line(color='red').encode(
y=alt.Y('signal2:Q', title='Signal 2'),
tooltip=[alt.Tooltip('timestamp:T', title='Time', format='%Y-%m-%d %H:%M:%S'), alt.Tooltip('signal2:Q', title='Signal 2')]
)

line3 = base.mark_line(color='green').encode(
y=alt.Y('signal3:Q', title='Signal 3'),
tooltip=[alt.Tooltip('timestamp:T', title='Time', format='%Y-%m-%d %H:%M:%S'), alt.Tooltip('signal3:Q', title='Signal 3')]
)

rule1 = alt.Chart(pd.DataFrame({'timestamp': [df['timestamp'][min_diff_index]]})).mark_rule(color='black').encode(
x='timestamp:T',
tooltip=[alt.Tooltip('timestamp:T', title='Time', format='%Y-%m-%d %H:%M:%S')]
)
rule2 = alt.Chart(pd.DataFrame({'timestamp': [df['timestamp'][min_diff_index + 10]]})).mark_rule(color='black').encode(
x='timestamp:T',
tooltip=[alt.Tooltip('timestamp:T', title='Time', format='%Y-%m-%d %H:%M:%S')]
)

mean_line = alt.Chart(pd.DataFrame({
'timestamp': [df['timestamp'][min_diff_index], df['timestamp'][min_diff_index + 10]],
'mean_signal3': [mean_signal3, mean_signal3]
})).mark_line(color='purple').encode(
x='timestamp:T',
y='mean_signal3:Q',
tooltip=[alt.Tooltip('timestamp:T', title='Time', format='%Y-%m-%d %H:%M:%S'), alt.Tooltip('mean_signal3:Q', title='Mean Signal 3')]
)

chart = alt.layer(line1, line2, line3, rule1, rule2, mean_line).properties(
width=800,
height=400,
title='Signals with Minimal Difference and Mean Value'
).add_params(interval)

chart.interactive()

Have you considered any alternative solutions?

No response