Python glob example

read_dir.py

#!/bin/python3

# run as
#     python3 read_dir.py test_dir

import os
import sys
import glob

import numpy as np
import matplotlib.pyplot as plt

file_dir = sys.argv[1]
file_template = 'gap{}.dat'

# setup dummy data
if not os.path.exists(file_dir):
    os.mkdir(file_dir)
    for n in range(20):
        with open(os.path.join(file_dir, file_template.format(n)), 'w') as f:
            for x in range(10):
                f.write(f"{x} {n*x}\n")

# read and plot data
plt.figure()
plt.title("Dummy Data")
plt.xlabel('x')
# https://docs.python.org/3/library/glob.html
# for data_file in glob.glob("dir/gap*.dat")
for data_file in glob.glob(os.path.join(file_dir, file_template.format('*'))):
    x, fx = np.loadtxt(data_file, unpack=True)
    plt.plot(x, fx, 'x-', label=data_file)
plt.legend()
plt.xlabel('x')
plt.ylabel('f(x)')

plt.show()