# Generate a signal with 100 data point

import numpy as np
t = np.linspace(0, 5, 100)
x = np.sin(t)

# Downsample it by a factor of 4

from scipy import signal
x_resampled = signal.resample(x, 25)

# Plot

from matplotlib import pyplot as plt
plt.figure(figsize=(5, 4))
plt.plot(t, x, label='Original signal')
plt.plot(t[::4], x_resampled, 'ko', label='Resampled signal')

plt.legend(loc='best')
plt.show()