[FIXED] Get all zeroes from matplotlib graph

Issue

How could I get a list of all the zeroes of a matplotlib graph? By zeroes I mean every coordinate where the y-value of my function is at 0 (very close to zero also works for what I'm trying to accomplish). My code and the graph it generates are down below.

THE .WAV FILE: https://drive.google.com/drive/folders/11nE0nyd9UPViicSIKNeiBqSNbdWGRbIl?usp=sharing

MY CODE:

from scipy.io import wavfile
import matplotlib.pyplot as plt
import numpy as np

samplerate, data = wavfile.read(r'C:\Users\jack_l\Downloads\louduntitled.wav')
length = data.shape[0] / samplerate
import matplotlib.pyplot as plt
import numpy as np
time = np.linspace(0., length, data.shape[0])
plt.plot(time, data[:, 1], label="Right channel")
plt.legend()
plt.xlabel("Time [s]")
plt.ylabel("Amplitude")
plt.show()

GRAPH:

Solution

I believe you want to find all times where the y-value is zero.

What about finding zero-crossings of the array data[:, 1] (here a), and use the returned indices to find the interpolated time values where y-value is zero.

CODE

import matplotlib.pyplot as plt
import numpy as np
from scipy.io import wavfile

# load data
samplerate, data = wavfile.read(r'C:\Users\jack_l\Downloads\louduntitled.wav')
length = data.shape[0] / samplerate
time = np.linspace(0., length, data.shape[0])

a = data[:, 1] # here put your data
zc_idxs = np.where(np.diff(np.sign(a)))[0] # indices of element before zero crossing
t_zero = []
for zc_i in zc_idxs: # interpolate each zero crossing
    t1 = time[zc_i]
    t2 = time[zc_i + 1]
    a1 = a[zc_i]
    a2 = a[zc_i + 1]
    t_zero.append(t1 + (0 - a1) * ((t2 - t1) / (a2 - a1)))

plt.plot(time, a, label="Right channel")
plt.plot(t_zero, np.zeros((len(t_zero), 1)), 'o')

Answered By - Radarrudi