Searching a .txt file for a specific number and extracting the corresponding data

[nrozman]

Can you show the code you have so far?

import numpy as np
import matplotlib.pyplot as plt

data_file1 = np.loadtxt('untitled.txt',delimiter='\t')     
p = data_file1[:,][:,0]              
t = data_file1[:,][:,1]      

plt.figure(1)
plt.rcParams['figure.figsize'] = [50, 50]
plt.plot(p, t,'c')
plt.xlabel('Periodicity [microns]')
plt.ylabel('Transmission')
plt.savefig('XRectangle.png')        # Saves the plot